ALBERT

Description: Due to a mistake during the production process, there was a spelling error in the Academic Editors’ names in the original published version [...]

Description: Living in the “era of social networking”, we are experiencing a data revolution, generating an astonishing amount of digital information every single day. Due to this proliferation of data volume, there has been an explosion of new application domains for information mined from social networks. In this paper, we leverage this “socially-generated knowledge” (i.e., user-generated content derived from social networks) towards the detection of areas-of-interest within an urban region. These large and homogeneous areas contain multiple points-of-interest which are of special interest to particular groups of people (e.g., tourists and/or consumers). In order to identify them, we exploit two types of metadata, namely location-based information included within geo-tagged photos that we collect from Flickr, along with plain simple textual information from user-generated tags. We propose an algorithm that divides a predefined geographical area (i.e., the center of Athens, Greece) into “tile”-shaped sub-regions and based on an iterative merging procedure, it aims to detect larger, cohesive areas. We examine the performance of the algorithm both in a qualitative and quantitative manner. Our experiments demonstrate that the proposed geo-clustering algorithm is able to correctly detect regions that contain popular tourist attractions within them with very promising results.

Description: In order to alleviate the pressure of information overload and enhance consumer satisfaction, personalization recommendation has become increasingly popular in recent years. As a result, various approaches for recommendation have been proposed in the past few years. However, traditional recommendation methods are still troubled with typical issues such as cold start, sparsity, and low accuracy. To address these problems, this paper proposed an improved recommendation method based on trust relationships in social networks to improve the performance of recommendations. In particular, we define trust relationship afresh and consider several representative factors in the formalization of trust relationships. To verify the proposed approach comprehensively, this paper conducted experiments in three ways. The experimental results show that our proposed approach leads to a substantial increase in prediction accuracy and is very helpful in dealing with cold start and sparsity.

Description: Acute Oak Decline (AOD) is a new condition affecting both species of native oak, Quercus robur and Quercus petraea, in Great Britain. The decline is characterised by a distinctive set of externally visible stem symptoms; bark cracks that “weep” dark exudate are found above necrotic lesions in the inner bark. Emergence holes of the buprestid beetle, Agrilus biguttatus are often also seen on the stems of oak within affected woodlands. This investigation assesses the extent to which the external symptoms of these two agents co-occur and reveals the spatial and temporal patterns present in affected woodland. Annual monitoring in eight affected woodlands showed that stem bleeding and emergence holes frequently occur on the same trees, with new emergence holes significantly more likely to occur when trees already have stem bleeds. Trials with coloured prism traps confirm A. biguttatus was present at all experimental sites. Beetle emergence is linked primarily to a few heavily declining trees, indicating that susceptibility may vary between hosts and that those with reduced health may be predisposed to AOD. Stem bleeds occur on trees in close proximity to the locations of trees with exit holes.

Description: Forests, Vol. 8, Pages 307: A Markov Chain Model for Simulating Wood Supply from Any-Aged Forest Management Based on National Forest Inventory (NFI) Data Forests doi: 10.3390/f8090307 Authors: Jari Vauhkonen Tuula Packalen Markov chain models have been applied for a long time to simulate forest dynamics based on transitions in matrices of tree diameter classes or areas of forest size and structure types. To date, area-based matrix models have been applied assuming either even-aged or uneven-aged forest management. However, both management systems may be applied simultaneously due to land-use constraints or the rationality of combining the systems, which is called any-aged management. We integrated two different Markov chain models, one for even-aged and another for uneven-aged forest management, in an area-based approach to analyze wood supply from any-aged forest management. We evaluate the impacts of parameterizing the model based on available data sets, namely permanent and temporary Finnish National Forest Inventory (NFI) sample plots and a plot-level simulator to determine transitions due to different types of thinning treatments, and present recommendations for the related methodological choices. Our overall observation is that the combined modelling chain simulated the development of both the even- and uneven-aged forest structures realistically. Due to the flexibility of the implementation, the approach is very well suited for situations where scenario assumptions need to be varied according to expected changes in silvicultural practices or land-use constraints, for example.

Description: Forests, Vol. 8, Pages 311: Lianas Abundance is Positively Related with the Avian Acoustic Community in Tropical Dry Forests Forests doi: 10.3390/f8090311 Authors: Branko Hilje Shauna Stack Arturo Sánchez-Azofeifa Dry forests are important sources of biodiversity where lianas are highly abundant given their ability to grow during times of drought and as a result of secondary growth processes. Lianas provide food and shelter for fauna such as birds, but there are no studies assessing the influence of liana abundance on birds in dry forests. Here we evaluate the influence of liana abundance on the avian acoustic community in the dry forests of Costa Rica at Santa Rosa National Park. We selected forest sites with different levels of liana abundance and set up automated sound recorders for data collection, analysis and estimation of the avian acoustic community. When the number of lianas increases, the avian acoustic community becomes more complex. Lianas could provide important direct and indirect resources for birds such as structure for shelter, protection, nesting and roosting, and food. The positive relationship that lianas have with birds is particularly important in dry forests where lianas are becoming highly abundant due to the level of forest disturbance and climate change, especially for some bird species that are restricted to this ecosystem. By validating the number of bird species detected in the recordings with the acoustic complexity index, we found that a higher acoustic complexity means higher species richness.

Description: Forests, Vol. 8, Pages 309: Allometric Equations for Estimating Compartment Biomass and Stem Volume in Mature Hybrid Poplars: General or Site-Specific? Forests doi: 10.3390/f8090309 Authors: Julien Fortier Benoit Truax Daniel Gagnon France Lambert We evaluated the extent to which general or site-specific allometric equations, using diameter at breast height (DBH) as a predictor, are more accurate for estimating stem volume, stem biomass, branch biomass, aboveground woody biomass, and coarse root biomass in 14 year-old plantations of Populus canadensis × Populus maximowiczii (clone DN × M-915508) located along an environmental gradient in southern Québec (eastern Canada). The effect of tree size and site on stem wood basic density, moisture content, and proportion of branch biomass was also evaluated. For stem volume, stem biomass, and aboveground biomass, site-specific and general models had comparable fit and accuracy, but lower Akaike’s Information Criterion (AICc) values were observed for the general models. For the branch and coarse root biomass, higher fit and accuracy and lower AICc values were observed for the site-specific models. Allometric trajectory changes (plastic allometry) across sites were mainly observed for coarse root biomass, branch biomass, and stem volume. On the low fertility site, allocation was increased to coarse roots and decreased to stem volume. Site-specific tradeoffs between tree architecture and stem wood density explained the relatively invariant allometry for the whole aboveground woody biomass across the plantation sites. On the high fertility sites, basic wood density was the lowest and declined as tree DBH increased. At all sites, stem wood moisture content and the proportion of branch biomass increased with DBH. Overall, this study showed that biomass allometry, tree architecture, and biomass quality are a function of both tree size and plantation environment in hybrid poplar. Allometric model selection (site-specific or general) should depend on the objective pursued (evaluation of yield, nutrient budget, carbon stocks).

Description: Forests, Vol. 8, Pages 308: Development of Sessile Oak and European Hornbeam Sprouts after Thinning Forests doi: 10.3390/f8090308 Authors: Zdeněk Adamec Jan Kadavý Barbora Fedorová Robert Knott Michal Kneifl Karel Drápela We observed the growth of juvenile sprouts at stool level in an oak-hornbeam selective coppice after selective thinning. We tested the relations of sprouting probability, number and height of new sprouts, and stool biometric characteristics with thinning intensity and light conditions. We compared the results between the two species. The sprouting probability, number of new sprouts, and height of new sprouts were modelled using different types of regression (logistic, generalized linear, and multiple linear regression) evaluated from 84 sessile oak (Quercus petraea Matt. Liebl.) and 139 European hornbeam (Carpinus betulus L.) stools with the same site conditions. There were no significant relations between sprouting probability and the tested parameters because nearly all stools re-sprouted. The growth (number and height) of new sprouts depended on the stool basal area before thinning and on thinning intensity. Light conditions (indirect site factor) only influenced the number of new European hornbeam sprouts in 2016 and the height of new sessile oak sprouts. The number of new sprouts in European hornbeam was higher than in sessile oak.

Description: Forests, Vol. 8, Pages 302: Assessing and Monitoring Forest Degradation in a Deciduous Tropical Forest in Mexico via Remote Sensing Indicators Forests doi: 10.3390/f8090302 Authors: Martin Romero-Sanchez Raul Ponce-Hernandez Assessing and monitoring forest degradation under national Monitoring, Verification and Reporting (MRV) systems in developing countries have been difficult to implement due to the lack of adequate technical and operational capacities. This study aims at providing methodological options for monitoring forest degradation in developing countries by using freely available remote sensing, forest inventory and ancillary data. We propose using Canopy Cover to separate, through a time series analysis approach using Landsat Imagery, forest areas with changes over time from sectors that report a “stable condition”. Above ground Biomass and Net Primary Productivity derived from remote sensing data were used to define thresholds for areas considered degraded. The approach was tested in a semi-deciduous tropical forest in the Southeast of Mexico. The results showed that higher rates of forest degradation, 1596 to 2865 ha year−1, occur in areas with high population densities. The results also showed that 43% of the forests of the study area remain with no evident signs of degradation, as determined by the indicators used. The approach and procedures followed allowed for the identification and mapping of the temporal and spatial distribution of forest degradation, based on the indicators selected, and they are expected to serve as the basis for operations of the Reduction of Emissions from Deforestation and Forest Degradation (REDD+) initiative in Mexico and other developing countries, provided appropriate adaptations of the methodology are made to the conditions of the area in turn.

Description: Forests, Vol. 8, Pages 316: Changes of Scots Pine Phyllosphere and Soil Fungal Communities during Outbreaks of Defoliating Insects Forests doi: 10.3390/f8090316 Authors: Lukas Beule Maren Grüning Petr Karlovsky Anne l-M-Arnold Outbreaks of forest pests increase with climate change, and thereby may affect microbial communities and ecosystem functioning. We investigated the structure of phyllosphere and soil microbial communities during defoliation by the nun moth (Lymantria monacha L.) (80% defoliation) and the pine tree lappet (Dendrolimus pini L.) (50% defoliation) in Scots pine forests (Pinus sylvestris L.) in Germany. Ribosomal RNA genes of fungi and bacteria were amplified by polymerase chain reaction (PCR), separated by denaturing gradient gel electrophoresis (DGGE), and subsequently sequenced for taxonomic assignments. Defoliation by both pests changed the structure of the dominant fungal (but not bacterial) taxa of the phyllosphere and the soil. The highly abundant ectomycorrhizal fungal taxon (Russula sp.) in soils declined, which may be attributed to insufficient carbohydrate supply by the host trees and increased root mortality. In contrast, potentially pathogenic fungal taxa in the phyllosphere increased during pest outbreaks. Our results suggest that defoliation of pines by insect pest, change the structure of fungal communities, and thereby indirectly may be contributing to aggravation of tree health.

Description: Forests, Vol. 8, Pages 317: Forest Structure and Composition Affect Bats in a Tropical Evergreen Broadleaf Forest Forests doi: 10.3390/f8090317 Authors: Emma Willcox William Giuliano Lauren Watine Daniel Mills Michael Andreu The lack of knowledge regarding many aerial insectivorous bats and their relationships with forest characteristics limits conservation decision-making for tropical rainforests and for this important bat group. Therefore, our objective was to understand the effects of forest structure and composition on these bats in the Neotropical evergreen broadleaf forest of Belize, Central America. We conducted bat monitoring and quantified 51 forest characteristics at 24 locations in the Chiquibul Forest Reserve (CFR) from May–July 2014. Simple linear and backward stepwise multiple regression analyses were used to examine relationships between bat richness and activity and forest characteristics. Bat genus richness and total activity were directly related to overstory canopy depth and inversely related to ≤4 structural characteristics. Lasiurus, Myotis, Promops, and Pteronotus spp. were affected by ≤7 forest characteristics; the responses were explained by preferences for less-cluttered, open space for flying and foraging and species-specific food and cover requirements. However, bat richness and activity were often unaffected by forest structure and composition in the CFR, suggesting that at this taxonomic level, bats may not be very sensitive to variation in forest characteristics, may not be very useful indicators of alteration, and may have some tolerance for disturbance and change.

Description: Forests, Vol. 8, Pages 320: Effects of the Antiozonant Ethylenediurea (EDU) on Fraxinus ornus L.: The Role of Drought Forests doi: 10.3390/f8090320 Authors: Elisabetta Salvatori Lina Fusaro Fausto Manes Ethylenediurea (EDU) is a synthetic chemical known to protect plants from the phytotoxic effects of tropospheric ozone (O3). Although many studies have proposed the use of EDU for studying the O3 effects under field conditions, its mechanism of action is not fully understood, and it is unclear whether it exerts a specific antiozonant action, or if it may also interact with other oxidative stresses. The aim of this work was to evaluate the effect of EDU on forest species in a Mediterranean environment where, during summer, vegetation is exposed to multiple oxidative stresses, such as O3 and drought. The experiment was conducted on Fraxinus ornus L. (Manna ash) plants growing in six mesocosms, three maintained under full irrigation, while the other three were subjected to drought for 84 days. In each mesocosm, three plants were sprayed every 15 days with 450 ppm EDU. Gas exchange and chlorophyll “a” fluorescence measurements carried out through the experimental period highlighted that EDU did not affect stomatal conductance and had an ameliorative effect on the functionality of drought-stressed plants, thus suggesting that it may act as a generic antioxidant. The implications of these findings for the applicability of EDU in field studies are discussed.

Description: Forests, Vol. 8, Pages 323: Differential Responses in Non-structural Carbohydrates of Machilus ichangensis Rehd. et Wils. and Taxus wallichiana Zucc. Var. chinensis (Pilg.) Florin Seedlings to Elevated Ozone Forests doi: 10.3390/f8090323 Authors: Jixin Cao Zhan Chen Hao Yu He Shang Tropospheric ozone (O3) enrichment could change the carbon (C) metabolism and decrease the C stock for tree species. To assess the differences in response of non-structural carbohydrates (NSCs) between Machilus ichangensis Rehd. et Wils. (M. ichangensis) and Taxus wallichiana Zucc. var. chinensis (Pilg.) Florin (T. wallichiana) with elevated O3, one-year-old container seedlings of the two species were grown with ambient air (AA), 100 ppb (elevated O3 treatment 1, E1-O3), and 150 ppb (elevated O3 treatment 2, E2-O3) treatments using open top chambers. During the experiment, net photosynthetic rate (Pn) of M. ichangensis and T. wallichiana were examined once each month from April to October. At the end of experiment, plants were harvested to examine the NSC concentrations and tissue C stocks. Results suggest elevated O3 significantly decreased Pn and total C stock for both M. ichangensis and T. wallichiana, while it also significantly decreased the NSC concentrations in the foliage of the two species, and the roots of T. wallichiana. However, the concentrations of NSCs and their components in other tissues did not change obviously. Significant increases in the ratio of soluble sugars to starch were observed in the foliage of M. ichangensis and the roots of T. wallichiana. For M. ichangensis, Pn was significantly and positively correlated with NSCs and their components only in foliage. In contrast, NSCs in both foliage and roots were significantly and positively correlated with Pn for T. wallichiana. Based on the results for Pn, total C stock, and NSC concentrations, M. ichangensis appeared more sensitive to elevated O3 than T. wallichiana. It is suggested that the strategies of C allocation in the two species are different with elevated O3.

Description: Forests, Vol. 8, Pages 326: Development of Northern White-Cedar (Thuja occidentalis L.) Plantations within and outside Deer Yards Forests doi: 10.3390/f8090326 Authors: Olivier Villemaire-Côté Jean-Claude Ruel Luc Sirois Regional surveys done over the last decades show a clear decline in abundance of Northern white-cedar (Thuja occidentalis L.) throughout its range. A lack of seed trees, difficulties in the establishment of natural regeneration and high browsing pressure caused by increasing deer populations have been identified as plausible causes. Current silvicultural strategies for cedar restoration recommend partial cutting to promote and release natural regeneration, but there is also a need to restore the species in areas where it became absent. Yet, little attention has been given to cedar plantations. This study provides a first characterisation of the effects of competition, silvicultural treatments and deer, moose and hare browsing on planted cedar growth, survival, and stem form. Pure and mixed cedar plantations aged 5–27 years located in Eastern Québec were sampled. Both inside and outside deer yards, planted cedars showed high survival rates and were generally subject to low browsing pressure, but 45% were forked. Cedars showed high growth rates and strong reaction to stand opening. Results suggest that at reduced competition levels, a 9-year browser exclusion could be sufficient to establish safe-from-browsing cedar stands of >3 m in height.

Description: Forests, Vol. 8, Pages 331: Forestry Best Management Practices Relationships with Aquatic and Riparian Fauna: A Review Forests doi: 10.3390/f8090331 Authors: Brooke Warrington W. Aust Scott Barrett W. Ford C. Dolloff Erik Schilling T. Wigley M. Bolding Forestry best management practices (BMPs) were developed to minimize water pollution from forestry operations by primarily addressing sediment and sediment transport, which is the leading source of pollution from silviculture. Implementation of water quality BMPs may also benefit riparian and aquatic wildlife, although wildlife benefits were not driving forces for BMP development. Therefore, we reviewed literature regarding potential contributions of sediment-reducing BMPs to conservation of riparian and aquatic wildlife, while realizing that BMPs also minimize thermal, nutrient, and chemical pollution. We reached five important conclusions: (1) a significant body of research confirms that forestry BMPs contribute to the protection of water quality and riparian forest structure; (2) data-specific relationships between forestry BMPs and reviewed species are limited; (3) forestry BMPs for forest road construction and maintenance, skid trails, stream crossings, and streamside management zones (SMZs) are important particularly for protection of water quality and aquatic species; (4) stream crossings should be carefully selected and installed to minimize sediment inputs and stream channel alterations; and (5) SMZs promote retention of older-age riparian habitat with benefits extending from water bodies to surrounding uplands. Overall, BMPs developed for protection of water quality should benefit a variety of riparian and aquatic species that are sensitive to changes in water quality or forest structure.

Description: Forests, Vol. 8, Pages 333: Changes in Soil Quality and Hydrological Connectivity Caused by the Abandonment of Terraces in a Mediterranean Burned Catchment Forests doi: 10.3390/f8090333 Authors: Aleix Calsamiglia Manuel Esteban Lucas-Borja Josep Fortesa Julián García-Comendador Joan Estrany Wildfires and agricultural activities are relevant factors affecting soil quality, hydrological cycle and sedimentary dynamics. Land abandonment leads to afforestation, which increases fire risk and land degradation. However, no studies have yet evaluated the effect of combining the two factors, which occur frequently in Mediterranean ecosystems. This study assessed the changes in soil quality caused by the abandonment of terraces in two microcatchments (<2.5 ha) affected distinctly by wildfires (once and twice burned) and in an unburned control microcatchment by analyzing soil quality parameters, biochemical indices and spatial patterns of hydrological and sediment connectivity. Soil samples were collected in thirty-six plots (25 m2) representing terraced and non-terraced areas within these microcatchments. Unburned non-terraced plots had higher organic matter content and higher microbiological and enzymatic activities than other plots. Plots in abandoned terraces had lower soil quality indices, regardless of the fire effect. Land abandonment induced changes in the spatial patterns of hydrological connectivity, leading to concentrated runoff, enhanced erosion and soil degradation. Fire also negatively affected soil quality in both terraced and non-terraced plots. However, microbiological communities had different positive post-fire recovery strategies (growth and activity), depending on the previous soil conditions and land uses, which is indicative of the resilience of Mediterranean soil ecosystems.

Description: Forests, Vol. 8, Pages 338: Updating Bark Proportions for the Estimation of Tropical Timber Volumes by Indigenous Community-Based Forest Enterprises in Quintana Roo, Mexico Forests doi: 10.3390/f8090338 Authors: Julieta Rosell Christian Wehenkel Abraham Pérez-Martínez José Arreola Palacios Sandra García-Jácome Marcela Olguín Sustainable management of tropical forests is essential for conserving the ecosystem services they provide and protecting the livelihoods of the millions of people who depend on these forests. Community-based forest management in Quintana Roo, Mexico, has shown that conserving forests while generating economic benefits is achievable in the tropics. However, this management is carried out with technical gaps that jeopardize sustainable use of these resources. Crucial among these gaps is a lack of equations for precise calculations of logged timber volumes. Current equations employ a proportion of bark volume (PBV) of 0.14 for mahogany and a flat 0.10 for species with dense woods, despite their wide variation in bark thickness. Here, using Meyer’s method, we calculated species-specific PBVs for the most commercially-important species in the Felipe Carrillo Puerto community-based logging operation. For most species, the new PBVs were smaller, indicating that wood volumes are currently underestimated. However, for two species, PBVs were higher. New values could influence the profits of the local enterprise and on the management of some of the most commercially-important species of Mexico’s tropical forests through changes in the numbers of individuals felled.

Description: Forests, Vol. 8, Pages 334: Climatic Factors Shape the Spatial Distribution of Concentrations of Triterpenoids in Barks of White Birch (Betula Platyphylla Suk.) Trees in Northeast China Forests doi: 10.3390/f8090334 Authors: Shenglei Guo Dehui Zhang Huanyong Wei Yinan Zhao Yibo Cao Tao Yu Yang Wang Xiufeng Yan Betulin, betulinic acid and lupeol are naturally occurring pentacyclic triterpenoids with significant medicinal values. Great amounts of triterpenoids are found in the bark of white birch (Betula platyphylla Suk.) trees, which can be affected by climatic factors along the geographical gradients. In this study, site-based data of triterpenoids’ (betulin, betulinic acid and lupeol) concentrations were determined in barks of white birch trees from 48 sites in Northeast China. Triterpenoid concentration in white birch tree barks did not change in response to any geographical gradients along latitudes, longitudes or elevations. Instead, concentrations of betulin and lupeol in birch tree barks increased with the increase of temperature and precipitation but declined with the increase of relative humidity. As a result, betulin concentration was higher in birch trees in the northeastern and southwestern parts of the study area, and lower in the central part of the study area in Northeast China. Although betulinic acid concentration did not change with climatic factors, its distribution pattern was similar to betulin concentration. Lupeol concentration was highest in the north-eastern part and along the southern and eastern boundaries in the study area. Our results can supply information for precondition of triterpenoids’ extraction for industrial production, which can be an available approach to solve the issue of bark waste processing of white birch.

Description: Forests, Vol. 8, Pages 341: Excessive Accumulation of Chinese Fir Litter Inhibits Its Own Seedling Emergence and Early Growth—A Greenhouse Perspective Forests doi: 10.3390/f8090341 Authors: Bo Liu Stefani Daryanto Lixin Wang Yanjuan Li Qingqing Liu Chong Zhao Zhengning Wang Litter accumulation can strongly influence plants’ natural regeneration via both physical and chemical mechanisms, but the relative influence of each mechanism on seedling establishment remains to be elucidated. Chinese fir (Cunninghamia lanceolata) is one of the most important commercial plantations in southern China, but its natural regeneration is poor, possibly due to its thick leaf litter accumulation. We used natural and plastic litter to study the effects of Chinese fir litter on its own seedling emergence and early growth, as well as to assess whether the effect is physical or chemical in nature. Results showed that high litter amount (800 g·m−2) significantly reduced seedling emergence and the survival rate for both natural and plastic litter. Low litter amount (200 g·m−2) exerted a slightly positive effect on root mass, leaf mass, and total mass, while high litter amount significantly inhibited root mass, leaf mass, and total mass for both natural and plastic litter. Root-mass ratio was significantly lower, and leaf-mass ratio was significantly greater under high litter cover than under control for both natural and plastic litter. Although the root/shoot ratio decreased with increasing litter amount, such effect was only significant for high litter treatment for both natural and plastic litter. Seedling robustness (aboveground biomass divided by seedling height) decreased with increasing litter amount, with high litter treatment generating the least robust seedlings. Because plastic and natural litter did not differ in their effects on seedling emergence and growth, the litter layer’s short-term influence is primarily physical. These data indicated that as litter cover increased, the initial slightly positive effects on seedling emergence and early growth could shift to inhibitory effects. Furthermore, to penetrate the thick litter layer, Chinese fir seedlings allocated more resources towards stems and aboveground growth at the expense of their roots. This study provided experimental evidence of litter amount as a key ecological factor affecting seedling development and subsequent natural regeneration of Chinese fir.

Description: Future Internet, Vol. 9, Pages 51: Local Path Planning of Driverless Car Navigation Based on Jump Point Search Method Under Urban Environment Future Internet doi: 10.3390/fi9030051 Authors: Kaijun Zhou Lingli Yu Ziwei Long Siyao Mo The Jump Point Search (JPS) algorithm is adopted for local path planning of the driverless car under urban environment, and it is a fast search method applied in path planning. Firstly, a vector Geographic Information System (GIS) map, including Global Positioning System (GPS) position, direction, and lane information, is built for global path planning. Secondly, the GIS map database is utilized in global path planning for the driverless car. Then, the JPS algorithm is adopted to avoid the front obstacle, and to find an optimal local path for the driverless car in the urban environment. Finally, 125 different simulation experiments in the urban environment demonstrate that JPS can search out the optimal and safety path successfully, and meanwhile, it has a lower time complexity compared with the Vector Field Histogram (VFH), the Rapidly Exploring Random Tree (RRT), A*, and the Probabilistic Roadmaps (PRM) algorithms. Furthermore, JPS is validated usefully in the structured urban environment.

Description: Forests, Vol. 8, Pages 344: Relationships between Plant Species Richness and Terrain in Middle Sub-Tropical Eastern China Forests doi: 10.3390/f8090344 Authors: Chuangye Song Mingchang Cao The objective of this research was to study the relation between species richness and topography in the middle sub-tropical area of Eastern China. A species richness survey was conducted along altitude in Kaihua County, Zhejiang Province, Eastern China. Topographic variables, such as altitude, slope, aspect, terrain roughness, relief degree and the topographical wetness index, were extracted from the digital elevation model. The Generalized Additive Model (GAM), the linear model and the quadratic model were used to fit response curves of species richness to topographic variables. The results indicated that altitude and the topographical wetness index have a significant relation to species richness. Species richness has a unimodal response to altitude and a linear response to the topographical wetness index. However, no significant correlations were observed between slope, aspect and species richness. The predicted species richness by GAM is significantly correlated with the observed species richness, whereas the prediction error tends to increase with the increment of species richness. This study furthered insights into the relationship between topography and plants’ diversity in the middle sub-tropical area of Eastern China.

Description: Forests, Vol. 8, Pages 352: Environmental Performance of Eastern Canadian Wood Pellets as Measured Through Life Cycle Assessment Forests doi: 10.3390/f8090352 Authors: Alejandro Padilla-Rivera Julie Barrette Pierre Blanchet Evelyne Thiffault Global demand for renewable energy has increased drastically over the last decade due to new climate change policies implemented in many jurisdictions. Wood pellets made from primary wood processing mill residues represent an attractive source of renewable energy that can be used in the environmental global challenge. However, the environmental impacts involved in their manufacture must be considered to measure the real benefits they can provide to the atmosphere. The general aim of this study was to evaluate the environmental impacts of wood pellet production at two Quebec plants using the Life Cycle Assessment (LCA) methodology and considering a gate-to-gate approach. The paper focuses on the different stages involved in wood pellet production; from the recovery of mill residues, through the pelletization process, to pellet bagging. The paper further expands to a cradle-to-grave analysis comparing the environmental footprints of producing and combusting 1 GJ of energy from wood pellets, natural gas and fossil fuel oil. The analysis suggested that the drying and the pelletizing stages were the largest negative factors affecting the environmental performance of wood pellet production. The comparison demonstrated the environmental advantage of using renewable rather than fossil sources of energy. Considering the growing interest in renewable energy, biomass in particular, and the lack of environmental information on wood pellets, this study could be useful not only for forest sector-related industries but also for the energy sector and policymakers.

Description: Forests, Vol. 8, Pages 295: A Review of Carbon Forest Development in China Forests doi: 10.3390/f8080295 Authors: Wei Zhou Peichen Gong Lan Gao This paper provides an overview of China’s climate mitigation policy related to the forestry sector, with a special focus on the development of carbon forests which are established to mitigate climate change. A total of 3.5 million ha of carbon forest were planted in the past decade. In recent years, the number of Voluntary Emission Reduction forest carbon projects has increased rapidly. The main challenges for future development of carbon forests under market mechanisms include increasing costs, uncertainty in the future supply and demand for China-certified emission reduction, and potential disputes between households and project developers.

Description: Forests, Vol. 8, Pages 296: Air Curtain Burners: A Tool for Disposal of Forest Residues Forests doi: 10.3390/f8080296 Authors: Eunjai Lee Han-Sup Han Open pile burning (OPB) forest residues have been limited due to several concerns, including atmospheric pollution, risk of fire spread, and weather conditions restrictions. Air Curtain Burner (ACB) systems could be an alternative to OPB and can avoid some of the negative effects that may result from OPB. The main objective was to compare the burning consumption rates and costs of two types of ACB machines, the S-220 and BurnBoss. In addition, we tested a hand-pile burning (HPB) consumption rate for a comparison with BurnBoss unit. The S-220’s burning consumption rates ranged between 5.7 and 6.8 green metric ton (GmT)/scheduled machine hour (SMH) at a cost between US $12.8 and US $10.8/GmT, respectively. Costs were 70% higher when using the BurnBoss unit. Burning residue consumption rates and cost of disposal were considerably different: they were highly dependent on machine size, species, and fuel age of forest residues. Particularly, BurnBoss test burned over 40% more than HPB method and produced clean burn by airflow. The results from this study suggest that ACBs can be a useful tool to dispose of forest residues piled in many forests areas with less concerns of air quality and fire escape risks.

Description: Forests, Vol. 8, Pages 305: Can Biomass Quality Be Preserved through Tarping Comminuted Roadside Biomass Piles? Forests doi: 10.3390/f8090305 Authors: Suzanne Wetzel Sylvain Volpe Janet Damianopoulos Sally Krigstin Storage conditions play a vital role in maintaining biomass quality as a suitable bioenergy feedstock. Research has shown that biomass undergoes significant changes under different storage conditions and that these may influence its suitability for various biorefining and bioenergy opportunities. This study explores the effects of different tarp covers on the properties of stored-comminuted forest harvest residue from the Great Lakes St. Lawrence Forest. Characteristics of the biomass were evaluated upon harvesting and after one year in storage. The physical state of the different tarps used for pile coverage was monitored onsite. Results indicated that tarp material considerably affects micro-climatic conditions inside piles, yielding variation in the characteristics of stored biomass over the storage period. While plastic based tarps were easier to work with and lasted longer than paper-based tarps, the paper-based tarps were more breathable and resulted in less degradation of biomass. However, the paper-based tarps did not maintain their structural integrity for the full duration of the storage period. Moisture content of original biomass (48.99%) increased to a maximum of 65.25% under plastic cover after 1 year of storage. This negatively influenced the net heating value of the biomass, causing it to decrease from 8.58 MJ/kg to 4.06 MJ/kg. Overall, the use of covers was not considered successful in preserving the original quality of biomass but may enhance its quality for other biorefinery opportunities.

Description: Forests, Vol. 8, Pages 306: Early Stage Forest Windthrow Estimation Based on Unmanned Aircraft System Imagery Forests doi: 10.3390/f8090306 Authors: Martin Mokroš Jozef Výbošťok Ján Merganič Markus Hollaus Iván Barton Milan Koreň Julián Tomaštík Juraj Čerňava Strong wind disturbances can affect large forested areas and often occur irregularly within a forest. Due to this, identifying damaged sites and estimating the extent of these losses are crucial for the harvesting management of salvage logging. Furthermore, the location should be surveyed as soon as possible after the disturbance to prevent the degradation of fallen trees. A fixed-wing type of unmanned aircraft system (UAS) with a compact digital camera was used in this study. The imagery was acquired on approximately 200 hectares where five large windthrow areas had occurred. The objective of the study was to determine the location of the windthrow areas using a semi-automatic approach based on the UAS imagery, and on the combination of UAS imagery with airborne laser scanning (ALS). The results were compared with reference data measured by global navigation satellite system (GNSS) devices. At the same time, windthrow areas were derived from Landsat imagery to investigate whether the UAS imagery would have significantly more accurate results. GNSS measurements and Landsat imagery are currently used in forestry on an operational level. The salvage logging was estimated for each forest stand based on the estimated areas and volume per hectare obtained from the forest management plan. The results from the UAS (25.09 ha) and the combined UAS/ALS (25.56 ha) methods were statistically similar to the reference GNSS measurements (25.39 ha). The result from Landsat, at 19.8 ha, was not statistically similar to the reference GNSS measurements or to the UAS and UAS/ALS methods. The estimate of salvage logging for the whole area, from UAS imagery and the forest management plan, overestimated the actual salvage logging measured by foresters by 4.93% (525 m3), when only the most represented tree species were considered. The UAS/ALS combination improved the preliminary results of determining windthrow areas which lead to decreased editing time for all operators. The UAS imagery shows potential for application to early-stage surveys of windthrow areas in forests. The advantages of this method are that it provides the ability to conduct flights immediately after the disturbance, the foresters do not need to walk within the affected areas which decreases the risk of injury, and allows flights to be conducted on cloudy days. The orthomosaic of the windthrow areas, as a by-product of data processing in combination with forest maps and forest road maps, can be used as a tool to plan salvage logging.

Description: Forests, Vol. 8, Pages 315: Climate Response of Larch and Birch Forests across an Elevational Transect and Hemisphere-Wide Comparisons, Kamchatka Peninsula, Russian Far East Forests doi: 10.3390/f8090315 Authors: Clara Deck Gregory Wiles Sarah Frederick Vladimir Matsovsky Tatiana Kuderina Rosanna D’Arrigo Olga Solomina Nicholas Wiesenberg Kamchatka’s forests span across the peninsula’s diverse topography and provide a wide range of physiographic and elevational settings that can be used to investigate how forests are responding to climate change and to anticipate future response. Birch (Betula ermanii Cham.) and larch (Larix gmelinii (Rupr.) Kuzen) were sampled at eight new sites and together with previous collections were compared with monthly temperature and precipitation records to identify their climate response. Comparisons show that tree-ring widths in both species are primarily influenced by May through August temperatures of the current growth year, and that there is a general increase in temperature sensitivity with altitude. The ring-width data for each species were also combined into regional chronologies. The resulting composite larch chronology shows a strong resemblance to a Northern Hemisphere (NH) tree-ring based temperature reconstruction with the larch series tracking NH temperatures closely through the past 300 years. The composite birch ring-width series more closely reflects the Pacific regional coastal late summer temperatures. These new data improve our understanding of the response of forests to climate and show the low frequency warming noted in other, more continental records from high latitudes of the Northern Hemisphere. Also evident in the ring-width record is that the larch and birch forests continue to track the strong warming of interior Kamchatka.

Description: Forests, Vol. 8, Pages 312: Effective Seed Dispersal and Fecundity Variation in a Small and Marginal Population of Pinus pinaster Ait. Growing in a Harsh Environment: Implications for Conservation of Forest Genetic Resources Forests doi: 10.3390/f8090312 Authors: Jesús Charco Martin Venturas Luis Gil Nikos Nanos Small-size, relict and marginal tree-species populations are a priority for conservation of forest genetic resources. In-situ conservation of these populations relies on adequate forest management planning based on knowledge and understanding of both ecological (i.e., recruitment or dispersal dynamics) and population-genetic processes (i.e., female reproductive success, gene flow or inbreeding). Here, we estimate the fecundity (or female reproductive success) of adult trees (i.e., the number of successfully established offspring/adult tree) and the effective dispersal distance distribution in the pine forest of Fuencaliente (southern Spain), a small-sized, marginal and relict population of maritime pine growing on a steep, craggy hill with just 312 reproductively active individuals. Previous studies have shown the population to present reduced allelic richness and suffer from genetic introgression from nearby exotic plantations of unknown origin. Between 2003 and 2004, we surveyed all adults and recruits and we measured several adult-specific covariates, including the number of cones of all adults. The population was found to be distributed into two nuclei with 268 (Stand 1) and 44 adults (Stand 2). We used inverse modeling to adjust several dispersal-and-fecundity models including a model with random variation in fecundity among adults (Unrestricted Fecundity or UF model). Results show that: (i) the average fecundity is 2.5–3.2 recruits/adult; (ii) the mean effective dispersal distance is restricted to 13–24 m and (iii) fecundity is most likely controlled by the spatial location of adult trees in Stand ,1 but it should be considered randomly distributed in Stand 2 (in this stand five adults mothered 80% of recruits). We conclude that the low fecundity in Stand 1 and the unequal fecundity in Stand 2 may decrease the population genetic diversity and lead to lower effective population size while the low average dispersal distance may reduce the probability of this population expanding to adjacent areas. In light of the results, we define the management priorities for in-situ conservation of this population.

Description: Forests, Vol. 8, Pages 314: Seasonal Dynamics of Litterfall in a Sub-Alpine Spruce-Fir Forest on the Eastern Tibetan Plateau: Allometric Scaling Relationships Based on One Year of Observations Forests doi: 10.3390/f8090314 Authors: Changkun Fu Wanqin Yang Bo Tan Zhenfeng Xu Yu Zhang Jiaping Yang Xiangyin Ni Fuzhong Wu Litterfall is the primary source of carbon and nutrients that determine soil fertility in forest ecosystems. Most current studies have focused on foliar litter, but the seasonal dynamics and allometric scaling relationships among different litter components (e.g., foliar litter, woody litter, reproductive litter, and epiphytic litter) are poorly understood. Here, we investigated the litter production of various litter components in a sub-alpine spruce-fir forest on the eastern Tibetan Plateau based on one year of observations (from August 2015 to July 2016). Our results showed that total litter production (LT) was 2380 kg·ha−1·year−1 (3% of the aboveground forest biomass), of which 73.6% was foliar litter (LF), 15.6% was woody litter (LW), 3.0% was reproductive litter (LR), 1.3% was epiphytic litter (LE), and 6.5% was miscellaneous material (LM). The total litterfall was bimodal (with peaks occurring in April and October) and was dominated by tree species (85.4% of LT, whereas shrubs accounted for 6.8% of LT). The litter production of evergreen species (68.4% of LT) was higher than that of deciduous species (23.8% of LT). Isometric relationships were observed between litter components and the total litter (i.e., LF∝LT0.99≈1 and LR∝LT0.98≈1), and allometric relationships were also found (i.e., LW∝LT1.40>1 and LM∝LT0.82<1). However, because some components did not exhibit obvious seasonal dynamics (i.e., LE), some relationships could not be expressed using allometric equations (i.e., LE versus LT, LF versus LE, LW versus LE, and LE versus LM). Thus, the different litter components showed different seasonal dynamics, and the total litter dynamics were primarily determined by the variation in foliar litter. In addition, the allometric relationships of the forest litterfall varied with the litter components, functional types (evergreen versus deciduous) and vertical structures (tree versus shrub). This study provides basic data and a new insight for future plant litter studies.

Description: Forests, Vol. 8, Pages 324: Functional Response Trait Analysis Improves Climate Sensitivity Estimation in Beech Forests at a Trailing Edge Forests doi: 10.3390/f8090324 Authors: Éva Salamon-Albert Gallusz Abaligeti Adrienne Ortmann-Ajkai Functional response traits influence the ability of species to colonize and thrive in a habitat and to persist under environmental challenges. Functional traits can be used to evaluate environment-related processes and phenomena. They also help to interpret distribution patterns, especially under limiting ecological conditions. In this study, we investigate landscape-scale functional distribution responses of beech forests in a climatic transitional zone in Europe. We construct empirical density distribution responses for beech forests by applying coping-resilience-failure climatic traits based on 27 bioclimatic variables, resulting in prevalence-decay-exclusion distribution response patterns. We also perform multivariate exploratory cluster analysis to reveal significant sets of response patterns from the resilience and adaptation aspects. Temperature-related distribution responses presented a prevalence-dominated functional pattern, with Annual mean temperature indicating the most favorable adaptation function. Precipitation indices showed climate-limited response patterns with the dominance of extinction function. Considering regional site-specific climate change projections, these continental beech forests could regress moderately due to temperature increase in the near future. Our results also suggest that both summer and winter precipitation could play a pivotal role in successful resilience. Functions and variables that indicate climate sensitivity can serve as a useful starting point to develop adaptation measures for regional forest management.

Description: Forests, Vol. 8, Pages 325: Effects of Cycle Length and Plot Density on Estimators for a National-Scale Forest Monitoring Sample Design Forests doi: 10.3390/f8090325 Authors: Francis Roesch Todd Schroeder James Vogt The resilience of a National Forest Inventory and Monitoring sample design can sometimes depend upon the degree to which it can adapt to fluctuations in funding. If a budget reduction necessitates the observation of fewer plots per year, some practitioners weigh the problem as a tradeoff between reducing the total number of plots and measuring the original number of plots over a greater number of years. Here, we explore some of the effects of differing plot intensities and cycle lengths on variants of three general classes of estimators for annual cubic meter per hectare volume, using a simulated population and appropriately-graduated sampling simulations. The simulations showed that an increase in cycle length yielded quite dramatic effects while differences due to a simulated reduction in plot intensity had more subtle effects.

Description: Future Internet, Vol. 9, Pages 49: Future Intelligent Systems and Networks Future Internet doi: 10.3390/fi9030049 Authors: Carmen de-Pablos-Heredero n/a

Description: Forests, Vol. 8, Pages 329: Differentiating Structural and Compositional Attributes across Successional Stages in Chilean Temperate Rainforests Forests doi: 10.3390/f8090329 Authors: Diego Ponce Pablo Donoso Christian Salas-Eljatib The landscape in the lowlands of south-central Chile is dominated by agricultural lands and forestry plantations of exotic species. Natural forests are restricted to successional forests, while old-growth forests are nearly absent. The lack of old-growth forests may deprive society from some ecosystem services. Both successional and old forests differ in their ecological functions and in the ecosystem services they can provide. To promote old-growth characteristics in successional forests, it becomes necessary to know which compositional and structural attributes differentiate forests along succession. We aim at identifying the differential attributes among successional and old-growth forests in the lowlands in the northern portion of the Valdivian Rainforests. We analyzed 19 variables in seven different forests and found statistically significant differences in 13 of them. A subset of these variables illustrated major patterns that differentiate successional stages, of which a few could be more easily controlled through management. The latter include lowering tree densities (from >3000 to <1500 trees per hectare), increasing volume of large trees, especially of shade-tolerant species, and structural heterogeneity (a Gini coefficient >0.7 represents older forests). While successional forest show a rapid recovery, forest managers would need to focus in controlling these attributes to increase their old-growth characteristics.

Description: Forests, Vol. 8, Pages 330: The Potential of Juniperus thurifera to Sequester Carbon in Semi-Arid Forest Soil in Spain Forests doi: 10.3390/f8090330 Authors: Elena Charro Amelia Moyano Raquel Cabezón The main purpose of this work is to show the influence of vegetation in the storage and stabilisation of organic carbon in semi-arid Juniperus thurifera (J. thurifera) forest soil in central Spain. The variability of the organic matter storage with factors such as sex, trunk diameter and the protection of the canopy of the tree has been analysed. The distribution of the soil organic carbon (SOC) into different fractions has also been determined, in order to estimate the stability of the organic matter. The results show that the SOC concentration has no dependence on the sex of the tree, but it increases with the diameter of the trunk and under the protection of the tree canopy. This study found that the organic matter of the J. thurifera forest soil has a high proportion of recalcitrant organic fraction, humin, which suggests that, given its organic matter stability, J. thurifera forest soils could be a real carbon sink. Consequently, the conservation of this type of old forest ecosystem is important for promoting carbon sequestration.

Description: Future Internet, Vol. 9, Pages 50: ARAAC: A Rational Allocation Approach in Cloud Data Center Networks Future Internet doi: 10.3390/fi9030050 Authors: Ahmad Quttoum Ayoub Alsarhan Abidalrahman Moh’d The expansion of telecommunication technologies touches almost all aspects life that we are living nowadays. Indeed, such technologies have emerged as a fourth essential utility alongside the traditional utilities of electricity, water, and gas. In this context, Cloud Data Center Networks (cloud-DCNs) have been proposed as a promising way to cope with such a high-tech era and with any expected trends in future computing networks. Resources of cloud-DCNs are leased to the interested users in the form of services, such services come in different models that vary between software, platform, and infrastructure. The leasing process of any service model starts with the users (i.e., service tenants). A tenant asks for the service resources, and the cloud-provider allocates the resources with a charge that follows a predefined cost policy. Cloud resources are limited, and those cloud providers have profit objectives to be satisfied. Thus, to comply with the aforementioned promise, the limited resources need to be carefully allocated. Existing allocation proposals in the literature dealt with this problem in varying ways. However, none proposes a win-win allocation model that satisfies both the providers and tenants. This work proposes A Rational Allocation Approach in Cloud Data Center Networks (ARAAC) that efficiently allocates the available cloud resources, in a way that allows for a win-win environment to satisfy both parties: the providers and tenants. To do so, ARAAC deploys the Second Best-Price (SBP) mechanism along with a behavioral-based reputation model. The reputation is built according to the tenants’ utilization history throughout their previous service allocations. The reputation records along with the adoption of the SBP mechanism allows for a locally free-equilibrium approach that allocates the available cloud-DCN resources in an efficient and fair manner. In ARAAC, through an auction scenario, tenants with positive reputation records are awarded by having the required resources allocated at prices that are lower than what they have offered. Compared to other benchmark models, simulation results show that ARAAC can efficiently adapt the behavior of those rational service-tenants to provide for better use of the cloud resources, with an increase in the providers’ profits.

Description: Forests, Vol. 8, Pages 328: Allometric Models to Predict Aboveground Woody Biomass of Black Locust (Robinia pseudoacacia L.) in Short Rotation Coppice in Previous Mining and Agricultural Areas in Germany Forests doi: 10.3390/f8090328 Authors: Christin Carl Peter Biber Dirk Landgraf Allan Buras Hans Pretzsch Black locust is a drought-resistant tree species with high biomass productivity during juvenility; it is able to thrive on wastelands, such as former brown coal fields and dry agricultural areas. However, research conducted on this species in such areas is limited. This paper aims to provide a basis for predicting tree woody biomass for black locust based on tree, competition, and site variables at 14 sites in northeast Germany that were previously utilized for mining or agriculture. The study areas, which are located in an area covering 320 km × 280 km, are characterized by a variety of climatic and soil conditions. Influential variables, including tree parameters, competition, and climatic parameters were considered. Allometric biomass models were employed. The findings show that the most important parameters are tree and competition variables. Different former land utilizations, such as mining or agriculture, as well as growth by cores or stumps, significantly influenced aboveground woody biomass production. The new biomass models developed as part of this study can be applied to calculate woody biomass production and carbon sequestration of Robinia pseudoacacia L. in short rotation coppices in previous mining and agricultural areas.

Description: Forests, Vol. 8, Pages 347: Rapid Shifts in Soil Nutrients and Decomposition Enzyme Activity in Early Succession Following Forest Fire Forests doi: 10.3390/f8090347 Authors: Joseph Knelman Emily Graham Scott Ferrenberg Aurélien Lecoeuvre Amanda Labrado John Darcy Diana Nemergut Steven Schmidt While past research has studied forest succession on decadal timescales, ecosystem responses to rapid shifts in nutrient dynamics within the first months to years of succession after fire (e.g., carbon (C) burn-off, a pulse in inorganic nitrogen (N), accumulation of organic matter, etc.) have been less well documented. This work reveals how rapid shifts in nutrient availability associated with fire disturbance may drive changes in soil enzyme activity on short timescales in forest secondary succession. In this study, we evaluate soil chemistry and decomposition extracellular enzyme activity (EEA) across time to determine whether rapid shifts in nutrient availability (1–29 months after fire) might control microbial enzyme activity. We found that, with advancing succession, soil nutrients correlate with C-targeting β-1,4-glucosidase (BG) EEA four months after the fire, and with N-targeting β-1,4-N-acetylglucosaminidase (NAG) EEA at 29 months after the fire, indicating shifting nutrient limitation and decomposition dynamics. We also observed increases in BG:NAG ratios over 29 months in these recently burned soils, suggesting relative increases in microbial activity around C-cycling and C-acquisition. These successional dynamics were unique from seasonal changes we observed in unburned, forested reference soils. Our work demonstrates how EEA may shift even within the first months to years of ecosystem succession alongside common patterns of post-fire nutrient availability. Thus, this work emphasizes that nutrient dynamics in the earliest stages of forest secondary succession are important for understanding rates of C and N cycling and ecosystem development.

Description: Forests, Vol. 8, Pages 346: Patterns of Early Postfire Succession of Alpine, Subalpine and Lichen-Woodland Vegetation: 21 Years of Monitoring from Permanent Plots Forests doi: 10.3390/f8090346 Authors: François Girard Serge Payette Ann Delwaide Field observations using chronosequences are helpful to study vegetation succession. This method allows to establish comparisons based on soil composition, stand structure, micro- and macrofossil remains from sites of different ages but on similar edaphic and topographic conditions. In the boreal forest, post-fire succession through time is triggered by climate, disturbance history (insect epidemics, fire and logging), latitude and altitude. The main objective of this research is to identify the main patterns of early post-fire succession, including similarities and differences in vegetation composition and attributes, of three contrasted ecosystems distributed along an altitudinal gradient. To do so, we have monitored the successional development of the alpine, subalpine and boreal lichen-woodland sites during the first 21 years (1991 to 2011) of post-fire sequence in eastern Canada 1991 to 2011. Each site was characterized by a different functional group that became established following fire. A rapid resurgence of ericaceous shrubs and lichens was observed in the lichen woodland and subalpine sites. Bryophyte and lichen species were not an important component of vegetation communities during the earlier stages of post-fire succession. For all three sites monitored, lichens were the last functional group to establish in the chronosequences. Herbs and mosses characterized the post-fire succession in alpine areas, the latter functional group established late in the chronosequence to cover >25% of the site after 15 years. Post-fire chronosequences in the three contrasted environments indicate that plant succession is a repetitive process often involving similar resilient plant assemblages.

Description: Forests, Vol. 8, Pages 351: Revisiting Wildland Fire Fuel Quantification Methods: The Challenge of Understanding a Dynamic, Biotic Entity Forests doi: 10.3390/f8090351 Authors: Thomas Duff Robert Keane Trent Penman Kevin Tolhurst Wildland fires are a function of properties of the fuels that sustain them. These fuels are themselves a function of vegetation, and share the complexity and dynamics of natural systems. Worldwide, the requirement for solutions to the threat of fire to human values has resulted in the development of systems for predicting fire behaviour. To date, regional differences in vegetation and independent fire model development has resulted a variety of approaches being used to describe, measure and map fuels. As a result, widely different systems have been adopted, resulting in incompatibilities that pose challenges to applying research findings and fire models outside their development domains. As combustion is a fundamental process, the same relationships between fuel and fire behaviour occur universally. Consequently, there is potential for developing novel fuel assessment methods that are more broadly applicable and allow fire research to be leveraged worldwide. Such a movement would require broad cooperation between researchers and would most likely necessitate a focus on universal properties of fuel. However, to truly understand fuel dynamics, the complex biotic nature of fuel would also need to remain a consideration—particularly when looking to understand the effects of altered fire regimes or changing climate.

Description: Forests, Vol. 8, Pages 350: How Reliable Are Heat Pulse Velocity Methods for Estimating Tree Transpiration? Forests doi: 10.3390/f8090350 Authors: Michael Forster Transpiration is a significant component of the hydrologic cycle and its accurate quantification is critical for modelling, industry, and policy decisions. Sap flow sensors provide a low cost and practical method to measure transpiration. Various methods to measure sap flow are available and a popular family of methods is known as heat pulse velocity (HPV). Theory on thermal conductance and convection, that underpins HPV methods, suggests transpiration can be directly estimated from sensor measurements without the need for laborious calibrations. To test this accuracy, transpiration estimated from HPV sensors is compared with an independent measure of plant water use such as a weighing lysimeter. A meta-analysis of the literature that explicitly tested the accuracy of a HPV sensors against an independent measure of transpiration was conducted. Data from linear regression analysis was collated where an R2 of 1 indicates perfect precision and a slope of 1 of the linear regression curve indicates perfect accuracy. The average R2 and slope from all studies was 0.822 and 0.860, respectively. However, the overall error, or deviation from real transpiration values, was 34.706%. The results indicate that HPV sensors are precise in correlating heat velocity with rates of transpiration, but poor in quantifying transpiration. Various sources of error in converting heat velocity into sap velocity and sap flow are discussed including probe misalignment, wound corrections, thermal diffusivity, stem water content, placement of sensors in sapwood, and scaling of point measurements to whole plants. Where whole plant water use or transpiration is required in a study, it is recommended that all sap flow sensors are calibrated against an independent measure of transpiration.

Description: Future Internet, Vol. 9, Pages 52: Design for Children’s Playful Learning with Robots Future Internet doi: 10.3390/fi9030052 Authors: Maria Lupetti Yuan Yao Haipeng Mi Claudio Germak This article presents an investigation of the implications of designing for children’s playful learning with robots. This study was carried out by adopting a Research through Design approach that resulted in the development of a novel low-anthropomorphic robot called Shybo. The article reports the main phases of the project: the preliminary and exploratory research that was carried out to define a list of design requirements; the design of the robot and its supplementary materials for carrying out playful learning experiences; and the evaluation of the project that involved both parents and children. The robot, in fact, was finally tested as part of a two-hour experience that engaged children in activities related to the associations between sounds and colours. The article presents and discusses the results of this evaluation to point out positive aspects of the experience, emerging issues and hints for future works. These are documented to share lessons learned that might be supportive of the general development of children’s playful learning and cognitive experiences with robots.

Description: Forests, Vol. 8, Pages 293: Environmental Factors Driving the Recovery of Bay Laurels from Phytophthora ramorum Infections: An Application of Numerical Ecology to Citizen Science Forests doi: 10.3390/f8080293 Authors: Guglielmo Lione Paolo Gonthier Matteo Garbelotto Phytophthora ramorum is an alien and invasive plant pathogen threatening forest ecosystems in Western North America, where it can cause both lethal and non-lethal diseases. While the mechanisms underlying the establishment and spread of P. ramorum have been elucidated, this is the first attempt to investigate the environmental factors driving the recovery of bay laurel, the main transmissive host of the pathogen. Based on a large dataset gathered from a citizen science program, an algorithm was designed, tested, and run to detect and geolocate recovered trees. Approximately 32% of infected bay laurels recovered in the time period between 2005 and 2015. Monte Carlo simulations pointed out the robustness of such estimates, and the algorithm achieved an 85% average rate of correct classification. The association between recovery and climatic, topographic, and ecological factors was assessed through a numerical ecology approach mostly based on binary logistic regressions. Significant (p < 0.05) coefficients and the information criteria of the models showed that the probability of bay laurel recovery increases in association with high temperatures and low precipitation levels, mostly in flat areas. Results suggest that aridity might be a key driver boosting the recovery of bay laurels from P. ramorum infections.

Description: Future Internet, Vol. 9, Pages 47: Cost-Aware IoT Extension of DISSECT-CF Future Internet doi: 10.3390/fi9030047 Authors: Andras Markus Attila Kertesz Gabor Kecskemeti In the age of the Internet of Things (IoT), more and more sensors, actuators and smart devices get connected to the network. Application providers often combine this connectivity with novel scenarios involving cloud computing. Before implementing changes in these large-scale systems, an in-depth analysis is often required to identify governance models, bottleneck situations, costs and unexpected behaviours. Distributed systems simulators help in such analysis, but they are often problematic to apply in this newly emerging domain. For example, most simulators are either too detailed (e.g., need extensive knowledge on networking), or not extensible enough to support the new scenarios. To overcome these issues, we discuss our IoT cost analysis oriented extension of DIScrete event baSed Energy Consumption simulaTor for Clouds and Federations (DISSECT-CF). Thus, we present an in-depth analysis of IoT and cloud related pricing models of the most widely used commercial providers. Then, we show how the fundamental properties (e.g., data production frequency) of IoT entities could be linked to the identified pricing models. To allow the adoption of unforeseen scenarios and pricing schemes, we present a declarative modelling language to describe these links. Finally, we validate our extensions by analysing the effects of various identified pricing models through five scenarios coming from the field of weather forecasting.

Description: Forests, Vol. 8, Pages 297: Comparison of Heat Transfer and Soil Impacts of Air Curtain Burner Burning and Slash Pile Burning Forests doi: 10.3390/f8080297 Authors: Woongsoon Jang Deborah Page-Dumroese Han-Sup Han We measured soil heating and subsequent changes in soil properties between two forest residue disposal methods: slash pile burning (SPB) and air curtain burner (ACB). The ACB consumes fuels more efficiently and safely via blowing air into a burning container. Five burning trials with different fuel sizes were implemented in northern California, USA. Soil temperature was measured at 1, 2, 3, 4, 6, and 8 cm depth. Immediately after burning, soil samples from two depths (0–10 and 10–20 cm) and ash samples were collected for analyzing organic matter; carbon and nitrogen content; and calcium, magnesium, and potassium concentrations. The highest temperature observed was 389 °C at 1 cm depth under the SPB. Mean peak temperatures were 133.2 °C and 162.2 °C for ACB and SPB, respectively. However, there were no significant differences in peak temperatures and duration of lethal soil temperatures (total minutes over 60 °C) between ACB and SPB. Heat transfer decreased rapidly as the soil depth increased. There is little evidence that any subsequent changes in soil chemical properties occurred, concluding that these small-scale burns had few negative impacts at our study site. Therefore, given the lack of extreme soil heating and more efficient and safer woody residue reduction, the ACB may be more effective than open SPB, especially where fire escape or long-term fire damage to soils are of concern.

Description: Future Internet, Vol. 9, Pages 48: Flow Shop Scheduling Problem and Solution in Cooperative Robotics—Case-Study: One Cobot in Cooperation with One Worker Future Internet doi: 10.3390/fi9030048 Authors: Ahmed Sadik Bodo Urban This research combines between two different manufacturing concepts. On the one hand, flow shop scheduling is a well-known problem in production systems. The problem appears when a group of jobs shares the same processing sequence on two or more machines sequentially. Flow shop scheduling tries to find the appropriate solution to optimize the sequence order of this group of jobs over the existing machines. The goal of flow shop scheduling is to obtain the continuity of the flow of the jobs over the machines. This can be obtained by minimizing the delays between two consequent jobs, therefore the overall makespan can be minimized. On the other hand, collaborative robotics is a relatively recent approach in production where a collaborative robot (cobot) is capable of a close proximity cooperation with the human worker to increase the manufacturing agility and flexibility. The simplest case-study of a collaborative workcell is one cobot in cooperation with one worker. This collaborative workcell can be seen as a special case of the shop flow scheduling problem, where the required time from the worker to perform a specific job is unknown and variable. Therefore, during this research, we implement an intelligent control solution which can optimize the flow shop scheduling problem over the previously mentioned case-study.

Description: Forests, Vol. 8, Pages 303: Land-Use Redistribution Compensated for Ecosystem Service Losses Derived from Agriculture Expansion, with Mixed Effects on Biodiversity in a NW Argentina Watershed Forests doi: 10.3390/f8080303 Authors: Ana Nanni Héctor Grau Areas of land abandonment and agriculture expansion usually differ in location and associated environmental characteristics; thus, land-use redistribution affects the provision of ecosystem services and biodiversity conservation. In a subtropical region undergoing land redistribution patterns characteristic of Latin America, we estimated 20-year changes in food production, above-ground carbon stocks and soil erosion due to land cover change, and the potential effects of such redistribution of forests on the diversity of birds and mammals. Between 1986 and 2006, despite only 0.3% of net forest cover change, 7% of the total area (ca. 280,000 has) switched between forest and non-forest covers. Food production increased by 46%, while the estimated ecosystem services changed by less than 10%. Forest carbon remained stable, with gains in montane humid forests compensating for losses in lowlands. Modeled soil erosion increased, but sediment accumulation at the watershed bottom remained stable. The responses of birds and mammals to forest redistribution differed and were stronger in birds. Due to the strong responses of birds to forest loss, lowland bird communities might be especially threatened by current land-use trends. Results suggest that land redistribution associated with the adjustment of agriculture towards soils suitable for mechanized agriculture can help mitigate associated losses in ecosystem services and biodiversity, but species and supporting services depending on easily-converted ecosystems require appropriate landscape management practices.

Description: Forests, Vol. 8, Pages 300: Use of Multi-Temporal UAV-Derived Imagery for Estimating Individual Tree Growth in Pinus pinea Stands Forests doi: 10.3390/f8080300 Authors: Juan Guerra-Hernández Eduardo González-Ferreiro Vicente Monleón Sonia Faias Margarida Tomé Ramón Díaz-Varela High spatial resolution imagery provided by unmanned aerial vehicles (UAVs) can yield accurate and efficient estimation of tree dimensions and canopy structural variables at the local scale. We flew a low-cost, lightweight UAV over an experimental Pinus pinea L. plantation (290 trees distributed over 16 ha with different fertirrigation treatments) to determine the tree positions and to estimate individual tree height (h), diameter (d), biomass (wa), as well as changes in these variables between 2015 and 2017. We used Structure from Motion (SfM) and 3D point cloud filtering techniques to generate the canopy height model and object-based image analysis to delineate individual tree crowns (ITC). ITC results were validated using accurate field measurements over a subsample of 50 trees. Comparison between SfM-derived and field-measured h yielded an R2 value of 0.96. Regressions using SfM-derived variables as explanatory variables described 79% and 86–87% of the variability in d and wa, respectively. The height and biomass growth estimates across the entire study area for the period 2015–2017 were 0.45 m ± 0.12 m and 198.7 ± 93.9 kg, respectively. Significant differences (t-test) in height and biomass were observed at the end of the study period. The findings indicate that the proposed method could be used to derive individual-tree variables and to detect spatio-temporal changes, highlighting the potential role of UAV-derived imagery as a forest management tool.

Description: Forests, Vol. 8, Pages 310: The Effect of Silver and Copper Nanoparticles on the Condition of English Oak (Quercus robur L.) Seedlings in a Container Nursery Experiment Forests doi: 10.3390/f8090310 Authors: Jacek Olchowik Roman Bzdyk Marcin Studnicki Magdalena Bederska-Błaszczyk Alexander Urban Marta Aleksandrowicz-Trzcińska Some studies indicate that metal nanoparticles can be used in plant cultivation as fungicides and growth stimulators. The aim of this study was to evaluate the effect of silver (AgNPs) and copper nanoparticles (CuNPs) on the growth parameters, on the extent of leaves infected by powdery mildew and on spontaneous ectomycorrhizal colonization of English oak (Quercus robur L.) seedlings growing in containers. Nanoparticles were applied to foliage four times during one vegetation season, at four concentrations: 0, 5, 25 and 50 ppm. The adsorption of NPs to leaves was observed by microscopical imaging (TEM). The tested concentrations of AgNPs and CuNPs did not have any significant effect on the growth parameters of the oak seedlings. TEM results showed disturbances in the shape of plastids, plastoglobules and the starch content of oak leaves treated with 50 ppm Cu- and AgNPs, while no changes in the ultrastructure of stems and roots of oak plants treated with NPs were observed. No significant difference in powdery mildew disease intensity was observed after NP foliar app lication. Four ectomycorrhizal taxa were detected on oak roots (Sphaerosporella brunnea, Thelephora terrestris, Paxillus involutus and Laccaria proxima). Oak seedlings treated (foliar) with CuNPs and AgNPs at 25 ppm were characterised by the highest degree of mycorrhization (respectively, 37.1% and 37.5%) among all treatments including the control treatment. None of the tested NPs manifested phytotoxicity in the examined Q. robur seedlings under container nursery conditions.

Description: Forests, Vol. 8, Pages 304: Edyn: Dynamic Signaling of Changes to Forests Using Exponentially Weighted Moving Average Charts Forests doi: 10.3390/f8090304 Authors: Evan Brooks Zhiqiang Yang Valerie Thomas Randolph Wynne Remote detection of forest disturbance remains a key area of interest for scientists and land managers. Subtle disturbances such as drought, disease, insect activity, and thinning harvests have a significant impact on carbon budgeting and forest productivity, but current change detection algorithms struggle to accurately identify them, especially over decadal timeframes. We introduce an algorithm called Edyn, which inputs a time series of residuals from harmonic regression into a control chart to signal low-magnitude, consistent deviations from the curve as disturbances. After signaling, Edyn retrains a new baseline curve. We compared Edyn with its parent algorithm (EWMACD—Exponentially Weighted Moving Average Change Detection) on over 3500 visually interpreted Landsat pixels from across the contiguous USA, with reference data for timing and type of disturbance. For disturbed forested pixels, Edyn had a mean per-pixel commission error of 31.1% and omission error of 70.0%, while commission and omission errors for EWMACD were 39.9% and 65.2%, respectively. Edyn had significantly less overall error than EWMACD (F1 = 0.19 versus F1 = 0.13). These patterns generally held for all of the reference data, including a direct comparison to other contemporary change detection algorithms, wherein Edyn and EWMACD were found to have lower omission error rates for a category of subtle changes over long periods.

Description: Forests, Vol. 8, Pages 322: Prediction of Forest Canopy and Surface Fuels from Lidar and Satellite Time Series Data in a Bark Beetle-Affected Forest Forests doi: 10.3390/f8090322 Authors: Benjamin Bright Andrew Hudak Arjan Meddens Todd Hawbaker Jennifer Briggs Robert Kennedy Wildfire behavior depends on the type, quantity, and condition of fuels, and the effect that bark beetle outbreaks have on fuels is a topic of current research and debate. Remote sensing can provide estimates of fuels across landscapes, although few studies have estimated surface fuels from remote sensing data. Here we predicted and mapped field-measured canopy and surface fuels from light detection and ranging (lidar) and Landsat time series explanatory variables via random forest (RF) modeling across a coniferous montane forest in Colorado, USA, which was affected by mountain pine beetles (Dendroctonus ponderosae Hopkins) approximately six years prior. We examined relationships between mapped fuels and the severity of tree mortality with correlation tests. RF models explained 59%, 48%, 35%, and 70% of the variation in available canopy fuel, canopy bulk density, canopy base height, and canopy height, respectively (percent root-mean-square error (%RMSE) = 12–54%). Surface fuels were predicted less accurately, with models explaining 24%, 28%, 32%, and 30% of the variation in litter and duff, 1 to 100-h, 1000-h, and total surface fuels, respectively (%RMSE = 37–98%). Fuel metrics were negatively correlated with the severity of tree mortality, except canopy base height, which increased with greater tree mortality. Our results showed how bark beetle-caused tree mortality significantly reduced canopy fuels in our study area. We demonstrated that lidar and Landsat time series data contain substantial information about canopy and surface fuels and can be used for large-scale efforts to monitor and map fuel loads for fire behavior modeling at a landscape scale.

Description: Forests, Vol. 8, Pages 318: Susceptibility of Several Northeastern Conifers to Fusarium circinatum and Strategies for Biocontrol Forests doi: 10.3390/f8090318 Authors: Jorge Martín-García Marius Paraschiv Juan Flores-Pacheco Danut Chira Julio Diez Mercedes Fernández Fusarium circinatum, the causal of pine pitch canker disease (PPC), is now considered among the most important pathogens of Pinaceae in the world. Although in Europe PPC is only established in the Iberian Peninsula, the potential endangered areas cover over 10 million hectares under the current host distribution and climatic conditions. It is therefore a priority to test the susceptibility of those species and their provenances, within Central and Northern Europe and find biological control agents (BCAs) against the disease. In this study, the susceptibility of Pinus sylvestris, P. mugo and Picea abies Romanian provenances to F. circinatum was tested using three inoculum doses. In parallel, the potential use of Trichoderma atroviride and Trichoderma viride as BCAs against F. circinatum was also tested. This study has demonstrated, for the first time, the susceptibility of P. mugo to F. circinatum. Likewise, the susceptibility of P. abies was also confirmed. The fact that the Romanian provenance of P. sylvestris has not been susceptible to F. circinatum suggests genetic resistance as a potential tool to manage the disease. This, together with the apparent effectiveness of Trichoderma species as BCAs, seems to indicate that an integrated management of the disease might be feasible.

Description: Forests, Vol. 8, Pages 335: The Impact of Assumed Uncertainty on Long-Term Decisions in Forest Spatial Harvest Scheduling as a Part of Sustainable Development Forests doi: 10.3390/f8090335 Authors: Jan Kašpar Robert Hlavatý Karel Kuželka Róbert Marušák The paper shows how the aspects of uncertainty in spatial harvest scheduling can be embedded into a harvest optimization model. We introduce an approach based on robust optimization that secures better scheduling schematics of the decision maker while eliminating a significant portion of uncertainty in the decisions. The robust programming approach presented in this paper was applied in a real management area of Central Europe. The basic harvest scheduling model with harvest-flow constraints was created. The uncertainty that is assessed here is due to forest inventory errors and growth prediction errors of stand volume. The modelled results were compared with randomly simulated errors of stand volume. The effects of different levels of robustness and uncertainty on harvest-flow were analyzed. The analysis confirmed that using the robust approach for harvest decisions always ensures significantly better solutions in terms of the harvested volume than the worst-case scenarios created under the same constraints. The construction of a mathematical model as well as the methodology of simulations are described in detail. The observed results confirmed obvious advantages of robust optimization. However, many problems with its application in forest management must still be solved. This study helps to address the need to develop and explore methods for decision-making under different kinds of uncertainty in forest management.

Description: Forests, Vol. 8, Pages 332: Effects of Drought on Xylem Anatomy and Water-Use Efficiency of Two Co-Occurring Pine Species Forests doi: 10.3390/f8090332 Authors: Dario Martin-Benito Kevin Anchukaitis Michael Evans Miren del Río Hans Beeckman Isabel Cañellas Exploring how drought influences growth, performance, and survival in different species is crucial to understanding the impacts of climate change on forest ecosystems. Here, we investigate the responses of two co-occurring pines (Pinus nigra and Pinus sylvestris) to interannual drought in east-central Spain by dendrochronological and wood anatomical features integrated with isotopic ratios of carbon (δ13C) and oxygen (δ18O) in tree rings. Our results showed that drought induces both species to allocate less carbon to build tracheid cell-walls but increases tracheid lumen diameters, particularly in the transition wood between early and latewood, potentially maximizing hydraulic conductivity but reducing resistance to embolism at a critical phase during the growing season. The thicker cell-wall-to-lumen ratio in P. nigra could imply that its xylem may be more resistant to bending stress and drought-induced cavitation than P. sylvestris. In contrast, the higher intrinsic water-use efficiency (iWUE) in P. sylvestris suggests that it relies more on a water-saving strategy. Our results suggest that narrower cell-walls and reduced growth under drought are not necessarily linked to increased iWUE. At our site P. nigra showed a higher growth plasticity, grew faster and was more competitive than P. sylvestris. In the long term, these sustained differences in iWUE and anatomical characters could affect forest species performance and composition, particularly under increased drought stress.

Description: Forests, Vol. 8, Pages 339: Traits and Resource Use of Co-Occurring Introduced and Native Trees in a Tropical Novel Forest Forests doi: 10.3390/f8090339 Authors: Jéssica Fonseca da Silva Ernesto Medina Ariel Lugo Novel forests are naturally regenerating forests that have established on degraded lands and have a species composition strongly influenced by introduced species. We studied ecophysiological traits of an introduced species (Castilla elastica Sessé) and several native species growing side by side in novel forests dominated by C. elastica in Puerto Rico. We hypothesized that C. elastica has higher photosynthetic capacity and makes more efficient use of resources than co-occurring native species. Using light response curves, we found that the photosynthetic capacity of C. elastica is similar to that of native species, and that different parameters of the curves reflected mostly sun light variation across the forest strata. However, photosynthetic nitrogen use-efficiency as well as leaf area/mass ratios were higher for C. elastica, and both the amount of C and N per unit area were lower, highlighting the different ecological strategies of the introduced and native plants. Presumably, those traits support C. elastica’s dominance over native plants in the study area. We provide empirical data on the ecophysiology of co-occurring plants in a novel forest, and show evidence that different resource-investment strategies co-occur in this type of ecosystem.

Description: Forests, Vol. 8, Pages 342: Proximate Causes of Land-Use and Land-Cover Change in Bannerghatta National Park: A Spatial Statistical Model Forests doi: 10.3390/f8090342 Authors: Sanchayeeta Adhikari Timothy Fik Puneet Dwivedi Land change modeling has become increasingly important in evaluating the unique driving factors and proximate causes that underlie a particular geographical location. In this article, a binary logistic regression analysis was employed to identify the factors influencing deforestation and simultaneous plantation driven reforestation in Bannerghatta National Park, located at the periphery of one of the fastest growing cities in India, i.e., Bangalore. Methodologically, this study explores the inclusion of different sub-regions and statistical population to address spatial autocorrelation in land change modeling. The results show negative relationship between deforestation and protected area status and edge of previous forest clearing. In addition, the deforestation models found differences in the processes that are affecting forest clearing in our two sub-periods of 1973–1992 and 1992–2007. The plantation driven reforestation in the region were attributed to distance to major towns, Bangalore city, rural centers and major and minor roads suggesting the importance of accessibility to market for heavy cash crops such as coconut palm and eucalyptus. Finally, the inclusion of different sub-regions and statistical population facilitated a better understanding of varying driving factors in different zones within the overall landscape.

Description: Forests, Vol. 8, Pages 343: Forest Structure Estimation from a UAV-Based Photogrammetric Point Cloud in Managed Temperate Coniferous Forests Forests doi: 10.3390/f8090343 Authors: Tetsuji Ota Miyuki Ogawa Nobuya Mizoue Keiko Fukumoto Shigejiro Yoshida Here, we investigated the capabilities of a lightweight unmanned aerial vehicle (UAV) photogrammetric point cloud for estimating forest biophysical properties in managed temperate coniferous forests in Japan, and the importance of spectral information for the estimation. We estimated four biophysical properties: stand volume (V), Lorey’s mean height (HL), mean height (HA), and max height (HM). We developed three independent variable sets, which included a height variable, a spectral variable, and a combined height and spectral variable. The addition of a dominant tree type to the above data sets was also tested. The model including a height variable and dominant tree type was the best for all biophysical property estimations. The root-mean-square errors (RMSEs) for the best model for V, HL, HA, and HM, were 118.30, 1.13, 1.24, and 1.24, respectively. The model including a height variable alone yielded the second highest accuracy. The respective RMSEs were 131.74, 1.21, 1.31, and 1.32. The model including a spectral variable alone yielded much lower estimation accuracy than that including a height variable. Thus, a lightweight UAV photogrammetric point cloud could accurately estimate forest biophysical properties, and a spectral variable was not necessarily required for the estimation. The dominant tree type improved estimation accuracy.

Description: Forests, Vol. 8, Pages 345: Towards a Theoretical Construct for Modelling Smallholders’ Forestland-Use Decisions: What Can We Learn from Agriculture and Forest Economics? Forests doi: 10.3390/f8090345 Authors: Kahlil Baker Gary Bull Kathy Baylis Richard Barichello Academic research on smallholders’ forestland-use decisions is regularly addressed in different streams of literature using different theoretical constructs that are independently incomplete. In this article, we propose a theoretical construct for modelling smallholders’ forestland-use decisions intended to serve in the guidance and operationalization of future models for quantitative analysis. Our construct is inspired by the sub-disciplines of forestry and agricultural economics with a crosscutting theme of how transaction costs drive separability between consumption and production decisions. Our results help explain why exogenous variables proposed in the existing literature are insufficient at explaining smallholders’ forestland-use decisions, and provide theoretical context for endogenizing characteristics of the household, farm and landscape. Smallholders’ forestland-use decisions are best understood in an agricultural context of competing uses for household assets and interdependent consumption and production decisions. Forest production strategies range from natural regeneration to intensive management of the forest resource to co-jointly produce market and non-market values. Due to transaction costs, decision prices are best represented by their shadow as opposed to market prices. Shadow prices are shaped by endogenous smallholder-specific preferences for leisure, non-market values, time, risk, and uncertainty. Our proposed construct is intended to provide a theoretical basis to assist modellers in the selection of variables for quantitative analysis.

Description: Forests, Vol. 8, Pages 355: Does the Slope of the Self-thinning Line Remain a Constant Value across Different Site Qualities?—An Implication for Plantation Density Management Forests doi: 10.3390/f8100355 Authors: Fangxing Ge Weisheng Zeng Wu Ma Jinghui Meng The self-thinning rule is regarded as one of the most important principles in plantation management. This rule, involving the assumption of a constant slope coefficient, has been universally applied when regulating stand density. In this study, we hypothesized that the slope coefficient can change significantly with changes in site quality. To test this hypothesis, we first grouped forest plots into 5 categories based on site index. Second, we produced the self-thinning line represented by the Reineke function for each of the 5 site categories, selecting fully stocked plots using reduced major axis regression. Third, the slope coefficients for the different categories were tested for significant differences. The results indicated that in general, the slope was significantly different with different site quality. In addition, we observed that the slope of the self-thinning line exhibited a steeper trend for sites of lower quality, which indicated increased self-thinning or reduced self-tolerance. Finally, we concluded that it is imperative to produce specific self-thinning lines for different site quality categories.

Description: Forests, Vol. 8, Pages 354: Variability in Larch (Larix Decidua Mill.) Tree-Ring Growth Response to Climate in the Polish Carpathian Mountains Forests doi: 10.3390/f8100354 Authors: Małgorzata Danek Monika Chuchro Adam Walanus The climate–growth relationship of larch (Larix decidua Mill.) in the Polish Carpathian Mountains was studied. We explored the spatial variability of the common signal observed in larch tree-ring growth, distinguished regions with uniform tree-ring growth patterns (dendrochronological signal), and determined the climatic factors that are particularly important for the growth of larch in this area. Uniformity in the growth reaction across the analyzed area was found in the positive response to May temperatures (significant correlation values range from 0.21 to 0.48); this indicates that the warm beginning of the growing season is important for larch growth across the study area. The signal variability from west to east found in the principal components analysis (PCA) results and differences in climate response between analyzed sites suggest their relation to increasing influence of the continental climate to the east. However, the observed relationship is not stable and does not occur systematically. Although the climate–growth response of larch at lower elevations is highly variable, a positive influence of July precipitation and a negative influence of April precipitation, and previous May and July temperature can be observed. The growth of larch from the highest study sites (Tatra Mountains, above 950 m a.s.l.) is related to temperature. This is manifested by a strong positive correlation with temperature during late spring, early summer, and the end of the previous growing season, and a negative or no response to late spring/summer precipitation. No relation between the observed correlations and slope aspect was found.

Description: Forests, Vol. 8, Pages 359: Climate-Induced Tree Growth Variations under the RCP 2.6 Scenario: A Case Study on the Southeastern Tibetan Plateau Forests doi: 10.3390/f8100359 Authors: Xianliang Zhang Fenghua Zou Zhenju Chen The relationship between climate and radial tree growth is traditionally used to reconstruct past climate conditions based on interannual tree-ring variations. However, few studies have used these climate-growth relationships to model the radial tree growth based on future climate projections. To detect the future forest dynamics, the climate-induced tree growth from 2006 to 2100 was projected using temperature changes under representative concentration pathway (RCP) 2.6 for the southeastern Tibetan Plateau. Radial tree growth was mainly controlled by annual mean temperature in this region. Based on the relationship between regional annual mean temperature and radial tree growth, a regression model was built that explained 62.5% of variance in the observed temperature record over the period 1911–2005. A period of unprecedented radial tree growth was found after 1998 when compared with the tree growth in the past 700 years. We found that radial tree growth would increase in the period 2006–2045 and decline after that period due to the projected temperature decrease. As forest productivity and biomass are expected to increase with the increased tree growth, these results suggest that temperature-limited systems could see future increases in productivity as growth limitations are lessened. The results of this research could be used to predict regional forest dynamics in the future.

Description: Future Internet, Vol. 9, Pages 54: Energy-Aware Adaptive Weighted Grid Clustering Algorithm for Renewable Wireless Sensor Networks Future Internet doi: 10.3390/fi9040054 Authors: Nelofar Aslam Kewen Xia Muhammad Haider Muhammad Hadi Wireless sensor networks (WSNs), built from many battery-operated sensor nodes are distributed in the environment for monitoring and data acquisition. Subsequent to the deployment of sensor nodes, the most challenging and daunting task is to enhance the energy resources for the lifetime performance of the entire WSN. In this study, we have attempted an approach based on the shortest path algorithm and grid clustering to save and renew power in a way that minimizes energy consumption and prolongs the overall network lifetime of WSNs. Initially, a wireless portable charging device (WPCD) is assumed which periodically travels on our proposed routing path among the nodes of the WSN to decrease their charge cycle time and recharge them with the help of wireless power transfer (WPT). Further, a scheduling scheme is proposed which creates clusters of WSNs. These clusters elect a cluster head among them based on the residual energy, buffer size, and distance of the head from each node of the cluster. The cluster head performs all data routing duties for all its member nodes to conserve the energy supposed to be consumed by member nodes. Furthermore, we compare our technique with the available literature by simulation, and the results showed a significant increase in the vacation time of the nodes of WSNs.

Description: Moso bamboo (Phyllostachys edulis) is one of the widely growing bamboo species in Asia. Because of its fast growth and aggressive rhizomes, it is reported to invade other forests and reduce the biodiversity of forest ecosystems. To determine the changes in soil nutrient conditions due to moso bamboo invasion, this research measured the difference in soil labile carbon (C) and nitrogen (N) contents in a Japanese cedar (Cryptomeria japonica) forest invaded by moso bamboo in central Taiwan. The content of soluble organic C (SbOC), measured by both KCl and hot-water extraction methods, was lower in bamboo than cedar soils. This observation agreed with the finding that the more easily decomposed SbOC could be lost with bamboo invasion. In addition, both SbOCKCl and SbOCHW contents were positively correlated with microbial biomass C content, so the decreased labile organic C content in bamboo soils may reduce microbial biomass production. Principal component analysis revealed soil organic C content (total organic C, SbOC and acid-hydrolysable C) as the most important soil parameter affected by the bamboo invasion, followed by microbial biomass N and NO3− contents in soils. The soil quality index model also agreed with the degraded soil quality with bamboo invasion. In conclusion, the invasion of moso bamboo reduced the C and N pools in bamboo soil and degraded the overall soil quality.

Description: Root rots are considered the most important forest diseases in Estonia, causing serious concern in forest management. The majority of trees infected by forest pathogens lack easily-detectable visual symptoms, making it difficult to detect decay in a tree. We assessed the general health condition of visually healthy trees in intensively managed Norway spruce (Picea abies L. Karst.) and Scots pine (Pinus sylvestris L.) stands with resistography in order to identify trees infected by root rot. We found that 8.0% of Norway spruces and 1.6% of Scots pines had well-developed internal decay on the root collar regardless of having no external symptoms of root rot. Visually healthy trees growing on permanent forest land experienced more decay than trees growing on former agricultural land. The radial proportion of decay of damaged trees was 61% in Norway spruces and 35% in Scots pines. The results suggest that resistography can be used as a reliable method for tree vitality assessment.

Description: Forests, Vol. 8, Pages 348: Long Non-Coding RNAs Responsive to Witches’ Broom Disease in Paulownia tomentosa Forests doi: 10.3390/f8090348 Authors: Zhe Wang Xiaoqiao Zhai Yabing Cao Yanpeng Dong Guoqiang Fan Paulownia witches’ broom (PaWB) disease caused by phytoplasmas is a fatal disease that leads to considerable economic losses. Long non-coding RNAs (lncRNAs) have been demonstrated to play critical regulatory roles in posttranscriptional and transcriptional regulation. However, lncRNAs and their functional roles remain poorly characterized in Paulownia. To identify lncRNAs and investigate their roles in the response to PaWB phytoplasmas, RNA sequencing was performed for healthy Paulownia tomentosa, PaWB-infected P. tomentosa, and for healthy and PaWB-infected P. tomentosa treated with 100 mg L−1 rifampicin. A total of 28,614 unique mRNAs and 3693 potential lncRNAs were identified. Comparisons between lncRNAs and coding genes indicated that lncRNAs tended to have shorter transcripts and fewer exon numbers, and displayed significant expression specificity. Based on our comparison scheme, 1063 PaWB-related mRNAs and 110 PaWB-related lncRNAs were identified; among them, 12 PaWB-related candidate target genes that were regulated by nine PaWB-related lncRNAs were characterized. This study provides the first catalog of lncRNAs expressed in Paulownia and gives a revealing insight into the molecular mechanism responsible for PaWB.

Description: Forests, Vol. 8, Pages 349: Structure and Composition of a Dry Mixed-Conifer Forest in Absence of Contemporary Treatments, Southwest, USA Forests doi: 10.3390/f8090349 Authors: Douglas Cram Pradip Saud Terrell Baker Dry mixed-conifer forests in the Southwest occupy an important ecological and hydrological role in upper watersheds. In the absence of reoccurring fire and silvicultural treatments over the last 50 years, we quantified forest structure and composition on prevailing north and south aspects of a dry mixed-conifer forest in southcentral New Mexico using mixed models and ordination analysis in preparation for an experiment in ecological restoration. Results indicated overstory and midstory were dominated by Douglas-fir (Pseudotsuga menziesii) and shade tolerant/fire intolerant white fir (Abies concolor) with interspersed mature aspen on north aspects, and Douglas-fir and Southwestern white pine (Pinus strobiformis) on south aspects. Ponderosa pine (Pinus ponderosa), which was historically co-dominant with Douglas-fir on north and south aspects, was subdominant on south aspects and almost entirely absent on north aspects. Regeneration was dominated by white fir saplings and seedlings on north aspects while ponderosa pine was completely absent. South aspect saplings and seedlings were characterized by Douglas-fir and Southwestern white pine, but almost no ponderosa pine. Ordination analysis characterized the effect of aspect on species composition. Understanding contemporary forest structure and composition is important when planning for desired future conditions that are to be achieved through ecological restoration using silvicultural techniques designed to foster resilience.

Description: Future Internet, Vol. 9, Pages 53: Towards a New Digital Era: Observing Local E-Government Services Adoption in a Chinese Municipality Future Internet doi: 10.3390/fi9030053 Authors: Yao Yang As electronic government services (e-government) evolve, traditional applications such as online portals are encountering challenges in a new digital era in which people thirst for more convenient, diverse channels of communication with their government. Despite the efforts devoted to the promotion of Social Networking Service (SNS) use in e-government for the past few years, empirical studies regarding this ongoing trend are still insufficient. In the local administration of China, a special collaboration between local governments and private Internet enterprises is happening: government services are imported into commercial SNS platforms known as WeChat and Weibo. This research conducts a case study of a Chinese municipality premised upon survey data (N = 605) collected in Chongqing. It examines the determinants of e-services adoption in four major local applications: two traditional government-led services “Government website portal” and “Government official app” (traditional government-led services), and two built-in government services on social networking applications “Weibo Government official account” “WeChat Public Services”. The paper aims to provide a closer understanding of current trends in local government e-services, or in this case, an innovative trial of Chinese e-government practices.

Description: Forests, Vol. 8, Pages 358: Available Nutrients Can Accumulate in Permanent Skid Trails Forests doi: 10.3390/f8100358 Authors: Kenton Stutz Helmer Schack-Kirchner Gerald Kändler Lea Landes Martin Linz Hannes Warlo Friederike Lang Forest harvesting removes and redistributes nutrients through felling and forwarding. Substantial quantities of nutrients can accumulate in brash mats on permanent skid trails, but their availability and uptake after multiple thinnings on soils susceptible to leaching are unknown. In this study, we modeled the deposition of base cations and phosphorus on a permanent skid trail after five thinnings of a Picea abies (L.) Karst. stand, and measured the resulting nutrient stocks in both the forest floor and mineral soil. An estimated 35%, 44%, 41%, and 61% of harvested Ca, K, Mg, and P, respectively, were redistributed to the skid trail. Of those deposited stocks, 32–65% of nutrients remained in decomposed brash material on the skid trail. Mineral soil stocks for Ca, K, and P were significantly higher in the skid trail than in the stand, which included minor increases in bioavailable pools. Skid trail root densities were not lower than the stand while bulk densities were only partially higher. Both would not limit nutrient uptake. There were no significant relations between needle nutrient concentrations and distance to the skid trail. Altogether, these results indicate that nutrient uptake from the skid trail was minimal despite their accumulation, chemical availability, and physical accessibility. This suggests that other factors such as liming and frequent thinning disturbances can repress uptake of available nutrients on skid trails.

Description: Forests, Vol. 8, Pages 357: Characterizing Rigging Crew Proximity to Hazards on Cable Logging Operations Using GNSS-RF: Effect of GNSS Positioning Error on Worker Safety Status Forests doi: 10.3390/f8100357 Authors: Ann Wempe Robert Keefe Logging continues to rank among the most lethal occupations in the United States. Though the hazards associated with fatalities are well-documented and safe distances from hazards is a common theme in safety education, positional relationships between workers and hazards have not been quantified previously. Using GNSS-RF (Global Navigation Satellite System-Radio Frequency) transponders that allow real-time monitoring of personnel, we collected positioning data for rigging crew workers and three common cable logging hazards: a log loader, skyline carriage, and snag. We summarized distances between all ground workers and each hazard on three active operations and estimated the proportion of time crew occupied higher-risk areas, as represented by geofences. We then assessed the extent to which positioning error associated with different stand conditions affected perceived worker safety status by applying error sampled in a separate, controlled field experiment to the operational data. Root mean squared error was estimated at 11.08 m in mature stands and 3.37 m in clearcuts. Simulated error expected for mature stands altered safety status in six of nine treatment combinations, whereas error expected for clearcuts affected only one. Our results show that canopy-associated GNSS error affects real-time geofence safety applications when using single-constellation American Global Positioning System transponders.

Description: Forests, Vol. 8, Pages 291: Carbon Emissions from Deforestation and Degradation in a Forest Reserve in Venezuela between 1990 and 2015 Forests doi: 10.3390/f8080291 Authors: Carlos Pacheco-Angulo Emilio Vilanova Inmaculada Aguado Sergio Monjardin Susana Martinez This study presents for the first time in Venezuela a joint analysis of deforestation and forest degradation processes, including its effects on carbon emissions. The Caparo Forest Reserve, located in the Western Plains ecoregion, in one of the national hot spots of deforestation, served as a case study using three different periods: 1990–2000, 2000–2010 and 2010–2015. In the context of the United Nations Framework Convention on Climate Change (UNFCCC) framework, the Practice Guidance for Land Use, Land-Use Change and Forestry from the Intergovernmental Panel on Climate Change (IPCC) was followed. These guidelines combine the activity data for the estimation of deforestation and degradation rates, in this case using open access Landsat imagery in conjunction with the TerraAmazon system with the emission factors, and these based on aboveground biomass (AGB) estimations using field data from permanent plots monitored during the study period. Deforestation was responsible of a net loss of −53,461 ha, while close to −3667 ha were classified as degraded forests during the 1990–2000 decade (−4.9% annual deforestation rate). An estimated area of −36,447 ha and −515 ha between 2000 and 2010 was affected by both processes (−4.3% annual forest loss), and −8111 ha and −737 ha between 2010 and 2015 (−3.2% per year). These processes were responsible for an estimated equivalent in carbon emissions of 2.21 ± 0.32 (SEM—Standard Error of the Mean) Mt CO2 year−1 (1990–2000), 1.56 ± 0.19 Mt CO2per year between 2000 and 2010, while 0.80 ± 0.11 Mt CO2 year−1 during the 2010–2015 period. Between 92.9% and 98.63% (mean 94.9%) of these emissions came from deforestation, and between 1.37% and 7.79% (mean 5.1%) from forest degradation. Using available data, at national scale, deforestation and forest degradation in Caparo represented, on average, 0.49% of the total CO2 emissions and about 1.79% of land use change related emissions for the same period in Venezuela. Finally, we briefly outline a set of elements so these results can serve as a baseline for the potential establishment of a Reducing Emissions from Deforestation and Forest Degradation (REDD+) strategy in the area.

Description: Forests, Vol. 8, Pages 292: Differential Effects of Coarse Woody Debris on Microbial and Soil Properties in Pinus densiflora Sieb. et Zucc. Forests Forests doi: 10.3390/f8080292 Authors: Seongjun Kim Guanlin Li Seung Hyun Han Hanna Chang Hyun-Jun Kim Yowhan Son Although coarse woody debris (CWD) is important for soil functioning, the mechanism which affects soil properties beneath CWD are unclear. Here, initial changes in microbial and soil properties were studied using homogenous CWD samples in eight Korean red pine (Pinus densiflora Sieb. et Zucc.) forests. For each forest, CWD samples (diameter: 11.1 ± 0.1 cm; length: 10.2 ± 0.0 cm) from similarly aged Korean red pine trees were laid on the mineral soil surface from May to June, 2016, and soils were sampled at points beneath CWD and at a distance of 1 m from the CWD after 1 year. Soils beneath the CWD had higher moisture but lower inorganic nitrogen (N) and a higher microbial biomass C (carbon)/N ratio than those sampled 1 m from the CWD. No differences in total C and N, labile C, pH, and C substrate utilization between the soils were significant. The difference in inorganic N between the soils decreased with increasing CWD decomposition, whereas that for microbial biomass fraction in total C and N increased correspondingly. Our results showed that soil microbial affinity for retaining N might become higher than that for retaining C under the presence of CWD, which possibly alters N availability and generates a spatial heterogeneity in forest soils.

Description: Forests, Vol. 8, Pages 290: An Analysis of Non-State and State Approaches for Forest Certification in Mexico Forests doi: 10.3390/f8080290 Authors: Emily García-Montiel Frederick Cubbage Alberto Rojo-Alboreca Concepción Lujan-Álvarez Eusebio Montiel-Antuna José Corral-Rivas Mexico has had a non-state forest certification system under the Forest Stewardship Council (FSC) since it was initiated in 1993, and developed a new state-sponsored Mexican Forest Certification System (MFCS) that began in 2008. Several analyses have been made of FSC forest certification in Mexico, but none have summarized the new MFCS system or compared its standards with FSC. We compare the implementation of the non-state FSC market forest certification with the state-sponsored MFCS system in Mexico, and review literature on forest certification, focusing on all studies in Mexico. MFCS has had substantial enrollment of more than 902,802 ha by 2016, compared to 900,388 ha for the more-established FSC program. MFCS can be acceptable for stand-alone forest certification, and might be viewed as a stepwise path to FSC certification. The merits of both systems are analyzed in terms of standard content, likely sustainable forestry practices, access to markets, and community forestry enterprises.

Description: Forests, Vol. 8, Pages 301: Climate-Induced Northerly Expansion of Siberian Silkmoth Range Forests doi: 10.3390/f8080301 Authors: Viacheslav I. Kharuk Sergei T. Im Kenneth J. Ranson Mikhail N. Yagunov Siberian silkmoth (Dendrolimus sibiricus Tschetv.) is a dangerous pest that has affected nearly 2.5 × 106 ha of “dark taiga” stands (composed of Abies sibirica, Pinus sibirica and Picea obovata) within the latitude range of 52°–59° N. Here we describe a current silkmoth outbreak that is occurring about half degree northward of its formerly documented outbreak range. This outbreak has covered an area of about 800 thousand ha with mortality of conifer stands within an area of about 300 thousand ha. The primary outbreak originated in the year 2014 within stands located on gentle relatively dry southwest slopes at elevations up to 200 m above sea level (a.s.l.) Then the outbreak spread to the mesic areas including northern slopes and the low-elevation forest belts along the Yenisei ridge. Within the outbreak area, the northern Siberian silkmoth population has reduced generation length from two to one year. Our study showed that the outbreak was promoted by droughts in prior years, an increase of the sum of daily temperatures (t > +10 °C), and a decrease in ground cover moisture. Within the outbreak area, secondary pests were also active, including the aggressive Polygraphus proximus bark borer beetle. The outbreak considered here is part of the wide-spread (panzonal) Siberian silkmoth outbreak that originated during 2014–2015 with a range of up to 1000 km in southern Siberia. Our work concludes that observed climate warming opens opportunities for Siberian silkmoth migration into historically outbreak free northern “dark taiga” stands.

Description: Forests, Vol. 8, Pages 299: The Impact of Water Content on Sources of Heterotrophic Soil Respiration Forests doi: 10.3390/f8080299 Authors: Kristin M. McElligott John R. Seiler Brian D. Strahm Heterotrophic respiration (RH) is a major flux of CO2 from forest ecosystems and represents a large source of uncertainty in estimating net ecosystem productivity (NEP) using regional soil respiration (RS) models. RH from leaf litter (RHL) may contribute greatly to annual RH estimates, but its contribution may be misrepresented due to the logistical and technical challenges associated with chamber-based field measurements of RHL. The purpose of this study was to evaluate the sensitivity of sources of RH (mineral soil-derived heterotrophic respiration [RHM] and leaf litter-derived heterotrophic respiration [RHL]) of a loblolly pine plantation (Pinus taeda L.) to varying soil and litter water content over the course of a dry down event. Additionally, we investigated whether fertilization influenced RHL and RHM to understand how forest nutrient management may impact forest soil carbon (C) dynamics. RHL was measured under dry conditions and at field capacity to evaluate water content controls on RHL, determine the duration of increased CO2 release following wetting, and evaluate the potential contribution to total RH. We also measured RHM inside collars that excluded plant roots and litter inputs, from field capacity until near-zero RHM rates were attained. We found that RHL was more sensitive to water content than RHM, and increased linearly with increasing litter water content (R2 = 0.89). The contribution of RHL to RH was greatest immediately following the wetting event, and decreased rapidly to near-zero rates between 3 and 10 days. RHM also had a strong relationship with soil water content (R2 = 0.62), but took between 200 and 233 days to attain near-zero RHM rates. Fertilization had no effect on RHM (p = 0.657), but significantly suppressed RHL rates after the wetting event (p < 0.009). These results demonstrate that there is great temporal variability in both CO2 released and the water content of differing sources of RH, and forest fertilization may largely impact forest floor C stocks. This variability may not be captured reliably using conventional weekly to monthly chamber-based field sampling efforts and could lead to over- or underestimation of RH. In the context of climate change, changes in the frequency and intensity of wetting and drying events will likely alter RHL and its contribution to RS. Separate consideration of RH sources and controls, along with increased field sampling frequency using chamber-based methodology under a broader range of specific environmental conditions, are likely needed to reduce variability in RH estimates and improve the accuracy of forest NEP predictions.

Description: Forests, Vol. 8, Pages 298: How Climate Change Will Affect Forest Composition and Forest Operations in Baden-Württemberg—A GIS-Based Case Study Approach Forests doi: 10.3390/f8080298 Authors: Ferréol Berendt Mathieu Fortin Dirk Jaeger Janine Schweier In order to accommodate foreseen climate change in European forests, the following are recommended: (i) to increase the number of tree species and the structural diversity; (ii) to replace unsuitable species by native broadleaved tree species, and (iii) to apply close-to-nature silviculture. The state forest department of Baden-Württemberg (BW) currently follows the concept of Forest Development Types (FDTs). However, future climatic conditions will have an impact on these types of forest as well as timber harvesting operations. This Geographic Information System (GIS)-based analysis identified appropriate locations for main FDTs and timber harvesting and extraction methods through the use of species suitability maps, topography, and soil sensitivity data. Based on our findings, the most common FDT in the state forest of BW is expected to be coniferous-beech mixed forests with 29.0% of the total forest area, followed by beech-coniferous (20.5%) and beech-broadleaved (15.4%) mixed forests. Where access for fully mechanized systems is not possible, the main harvesting and extraction methods would be motor manual felling and cable yarding (29.1%). High proportions of large dimensioned trees will require timber extraction using forestry tractors, and these will need to be operated from tractor roads on sensitive soils (23.0%), and from skid trails on insensitive soils (18.4%).

Description: Forests, Vol. 8, Pages 294: Age-Effect Radial Growth Responses of Picea schrenkiana to Climate Change in the Eastern Tianshan Mountains, Northwest China Forests doi: 10.3390/f8090294 Authors: Liang Jiao Yuan Jiang Mingchang Wang Wentao Zhang Yiping Zhang The climate changed from warm-dry to warm-wet during the 1960s in northwest China. However, the effects of climate change on the response of radial growth from different age-class trees have been unclear. We assessed the age-effect radial growth responses in three age-classes (ml-old: ≥200 years, ml-middle: 100–200 years and ml-young: <100 years) of Schrenk spruce (Picea schrenkiana Fisch. et Mey.) in the eastern Tianshan Mountains. The primary conclusions were as follows: the developed chronologies of the three age-class trees contained significant climate information and exhibited high similarity as shown by calculating the statistical parameter characteristics and Gleichlaufigkeit index. The three age-class trees were consistent for annual variation trends of radial growth under climate change, showing similar fluctuations, tree-ring width chronology trends, time trends of cumulative radial growth, and basal area increment. In addition, the old and middle trees were found to be more sensitive to climate variability by analyzing Pearson correlations between radial growth from three age-class trees and climate factors. As a result, the drought caused by reduced total precipitation and higher mean temperature was a limiting factor of tree radial growth, and the trees with ages of up to 100 years were more suitable for studies on the growth-climate relationships. Thus, the studies on age-effect radial growth responses of Schrenk spruce can help not only in understanding the adaptive strategies of different-age trees to climate change, but also provide an accurate basis for climate reconstruction.

Description: Forests, Vol. 8, Pages 313: Spatio-Temporal Linkages between Declining Arctic Sea-Ice Extent and Increasing Wildfire Activity in the Western United States Forests doi: 10.3390/f8090313 Authors: Paul Knapp Peter Soulé We examined relationships between monthly Arctic sea-ice extent (ASIE) and annual wildfire activity for seven regions in the western United States during 1980–2015 to determine if spatio-temporal linkages exist between ASIE, upper-level flow, and surface climatic conditions conducive to western U.S. wildfire activity. Winter ASIE had significant (p < 0.05) negative relationships with annual wildfire area burned (rs = −0.391 − −0.683), with the strongest relationship occurring in the Northern Rockies. We explored spatial linkages between ASIE and 300-hPa flow (+), temperature (+), precipitation (−), and soil moisture (+) using monthly values of ASIE and gridded values for the climatic parameters. Relationships were best expressed between January ASIE and conditions in the current-year July over the Pacific Northwest and Northern Rockies. Reduced wintertime ASIE is teleconnected with increased ridging in summertime 300-hPa flow over the western U.S., resulting in warmer and drier conditions during peak fire season. Our findings suggest that reductions in ASIE are one of the driving forces behind the increasing annual trend (>36,000 ha) in area burned in the western U.S. since 1980.

Description: Forests, Vol. 8, Pages 319: Improved Outbreak Prediction for Common Pine Sawfly (Diprion pini L.) by Analyzing Floating ‘Climatic Windows’ as Keys for Changes in Voltinism Forests doi: 10.3390/f8090319 Authors: Katrin Möller Rainer Hentschel Aline Wenning Jens Schröder The biology and population dynamics of pine sawfly Diprion pini L. are extremely complex and variable. Among other factors, climatic conditions determine the potential for mass outbreaks of the species. In this paper, we investigate this influence and describe a statistical approach to identify responsible climatic variables in floating time windows, thus identifying the factors responsible for the transition from latency to outbreak events. Analyses were built upon a data base comprising outbreak events and fine-scaled climatic data for the period 2002–2016 for a model region in the state of Brandenburg, Germany. By applying Random Forest statistic classification analyses, we isolated a set of four variables. They cover precipitation, temperature, and potential evapotranspiration in distinct periods during the current and the previous year. These periods are not fixed in their position but attached to the floating phenological date of bud burst of the host species Pinus sylvestris L. The complete set of variables was able to distinguish forests likely to be defoliated from those not threatened at high probabilities (95% true-positive rate, 98% true-negative rate). Theidentified climatic windows offer insights into population dynamics in the study region, support adjustments in current monitoring algorithms, and indicate starting points for further investigations covering other regions or different years.

Description: Forests, Vol. 8, Pages 321: Integrating Climate Change and Land Use Impacts to Explore Forest Conservation Policy Forests doi: 10.3390/f8090321 Authors: Hyeyeong Choe James H. Thorne This study uses a scenario-based approach to ask what are the varying impacts to forest extent and biodiversity from sixteen climate change and forest conversion scenario combinations, and what do they suggest about future forest conservation policy directions? We projected these combinations onto existing forests in South Korea and grouped them into four forest categories. We used species distribution models for 1031 climate vulnerable plant species as a biodiversity index, and found that species richness loss due to forest conversion could be reduced significantly by deploying the scenarios which preserve forest areas that are climatically suitable for these species. Climate-suitable forest areas declined sharply and moved northward as future temperatures increase, and climate-suitable areas lost the highest proportion of forest extent under the current trend of forest conversion. We suggest climate refugia, defined as existing forests with suitable future climates, be protected from land use conversion as a way to preserve forest biodiversity. These spatially explicit results can be used for developing forest conservation policies, and the methods may be applicable to other forested regions. However, planners should consider the assumptions and uncertainties of climate projections, species distribution models, and land use trends when addressing forest biodiversity conservation.

Description: Forests, Vol. 8, Pages 327: New Allometric Equations to Support Sustainable Plantation Management of Rosewood (Aniba rosaeodora Ducke) in the Central Amazon Forests doi: 10.3390/f8090327 Authors: Pedro Krainovic Danilo Almeida Paulo Sampaio Rosewood (Aniba rosaeodora Ducke) is an endangered Amazonian tree species which produces one of the most valuable essential oils in the world. The species is used in silvicultural systems which are seen as a means to reducing the pressure of exploitation of natural rosewood populations. There are no specific equations for rosewood plantations, and therefore generalized equations are inappropriate for the species in commercial systems. This study presents allometric equations from 144 trees sampled in different rosewood plantations of Central Amazonia. The equations generated were compared with an equation used in forest management to estimate wood volume and another one recommended by law for rosewood biomass. The equation suggested by current legislation underestimates the actual values by more than 70% making the viable use of this equation impossible in commercial plantations. The equations generated to estimate the volume and biomass serve as an alternative to the need to develop specific equations for each area and age of the plant. The generic equation for the species is consistent for fresh mass management, with a generalized R2 of 0.80 and an underestimation of 0.33%. The equation for crown fresh mass estimation presented a generalized R2 of 0.32 and an underestimation of 0.24%. The underestimation of the mass production by rosewood plantations represents a serious impediment to this forest activity. The allometric equations developed are highly applicable under different conditions and management options and should be suggested by the legal provisions regulating rosewood-related activity in Central Amazonia.

Description: Forests, Vol. 8, Pages 336: Tree Growth Rings in Tropical Peat Swamp Forests of Kalimantan, Indonesia Forests doi: 10.3390/f8090336 Authors: Martin Worbes Hety Herawati Christopher Martius Tree growth rings are signs of the seasonality of tree growth and indicate how tree productivity relates to environmental factors. We studied the periodicity of tree growth ring formation in seasonally inundated peatlands of Central Kalimantan (southern Borneo), Indonesia. We collected samples from 47 individuals encompassing 27 tree species. About 40% of these species form distinct growth zones, 30% form indistinct ones, and the others were classified as in between. Radiocarbon age datings of single distinct growth zones (or “rings”) of two species showing very distinct rings, Horsfieldia crassifolia and Diospyros evena, confirm annual growth periodicity for the former; the latter forms rings in intervals of more than one year. The differences can be explained with species-specific sensitivity to the variable intensity of dry periods. The anatomical feature behind annual rings in Horsfieldia is the formation of marginal parenchyma bands. Tree ring curves of other investigated species with the same anatomical feature from the site show a good congruence with the curves from H. crassifolia. They can therefore be used as indicator species for growth rate estimations in environments with weak seasonality. The investigated peatland species show low annual growth increments compared to other tropical forests.

Description: Forests, Vol. 8, Pages 337: Vertical Ozone Gradients above Forests. Comparison of Different Calculation Options with Direct Ozone Measurements above a Mature Forest and Consequences for Ozone Risk Assessment Forests doi: 10.3390/f8090337 Authors: Giacomo Gerosa Riccardo Marzuoli Beatrice Monteleone Maria Chiesa Angelo Finco The estimation of the ozone (O3) stomatal dose absorbed by a forest is a crucial step for O3 risk assessment. For this purpose, data on O3 concentrations at the forest top-canopy are needed. However, O3 is barely measured at that height, while more often it is measured at a lower height above a different surface, typically a grassland near to the forest edge. The DO3SE model for O3 stomatal flux calculation estimates the top-canopy O3 concentration in near neutral stability conditions. However, near-neutrality is quite rare in the field, particularly in southern Europe. In this work, we present a modification of the DO3SE gradient calculation scheme to include the atmospheric stability. The performance of the new calculation scheme was tested against the direct measurements above a mature forest. Different gradient estimation options were also tested and evaluated. These options include simplified gradient calculation schemes and the techniques of the tabulated gradients described in the UN/ECE Mapping Manual for O3 risk assessment. The results highlight that the inclusion of the atmospheric stability in the DO3SE model greatly improves the accuracy of the stomatal dose estimation. However, the simpler technique of the tabulated gradients had the best performance on a whole-season time frame.

Description: Forests, Vol. 8, Pages 340: Individual Tree Detection from Unmanned Aerial Vehicle (UAV) Derived Canopy Height Model in an Open Canopy Mixed Conifer Forest Forests doi: 10.3390/f8090340 Authors: Midhun Mohan Carlos Silva Carine Klauberg Prahlad Jat Glenn Catts Adrián Cardil Andrew Hudak Mahendra Dia Advances in Unmanned Aerial Vehicle (UAV) technology and data processing capabilities have made it feasible to obtain high-resolution imagery and three dimensional (3D) data which can be used for forest monitoring and assessing tree attributes. This study evaluates the applicability of low consumer grade cameras attached to UAVs and structure-from-motion (SfM) algorithm for automatic individual tree detection (ITD) using a local-maxima based algorithm on UAV-derived Canopy Height Models (CHMs). This study was conducted in a private forest at Cache Creek located east of Jackson city, Wyoming. Based on the UAV-imagery, we allocated 30 field plots of 20 m × 20 m. For each plot, the number of trees was counted manually using the UAV-derived orthomosaic for reference. A total of 367 reference trees were counted as part of this study and the algorithm detected 312 trees resulting in an accuracy higher than 85% (F-score of 0.86). Overall, the algorithm missed 55 trees (omission errors), and falsely detected 46 trees (commission errors) resulting in a total count of 358 trees. We further determined the impact of fixed tree window sizes (FWS) and fixed smoothing window sizes (SWS) on the ITD accuracy, and detected an inverse relationship between tree density and FWS. From our results, it can be concluded that ITD can be performed with an acceptable accuracy (F > 0.80) from UAV-derived CHMs in an open canopy forest, and has the potential to supplement future research directed towards estimation of above ground biomass and stem volume from UAV-imagery.

Description: The western United States faces significant forest management challenges after severe bark beetle infestations have led to substantial mortality. Minimizing costs is vital for increasing the feasibility of management operations in affected forests. Multi‐transmitter Global Navigation Satellite System (GNSS)‐radio frequencies (RF) technology has applications in the quantification and analysis of harvest system production efficiency and provision of real‐time operational machine position, navigation, and timing. The aim of this study was to determine the accuracy with which multi‐transmitter GNSS‐RF captures the swinging and forwarding motions of ground based harvesting machines at varying transmission intervals. Assessing the accuracy of GNSS in capturing intricate machine movements is a first step toward development of a real‐time production model to assist timber harvesting of beetle‐killed lodgepole pine stands. In a complete randomized block experiment with four replicates, a log loader rotated to 18 predetermined angles with GNSS‐RF transponders collecting and sending data at two points along the machine boom (grapple and heel rack) and at three transmission intervals (2.5, 5.0, and 10.0 s). The 2.5 and 5.0 s intervals correctly identified 94% and 92% of cycles at the grapple and 92% and 89% of cycles at the heel, respectively. The 2.5 s interval successfully classified over 90% of individual cycle elements, while the 5.0 s interval returned statistically similar results. Predicted swing angles obtained the highest level of similarity to observed angles at the 2.5 s interval. Our results show that GNSS‐RF is useful for realtime, model‐based analysis of forest operations, including woody biomass production logistics.

Description: Climate Change policies are playing an ever-increasing role in global development strategies and their implementation gives rise to often-unforeseen social conflicts and environmental degradations. A landscape approach to analyzing forest-based Climate Change Mitigation policies (CCM) and land grabs in the Prey Lang Forest landscape, Cambodia revealed two Korea-Cambodia partnership projects designed to increase forest cover that are juxtaposed in this paper. Case study data revealed a REDD+ project with little negative impact or social conflict in the project area and an Afforestation/Reforestation (A/R) project that created both social and ecological conflicts. The study concludes that forest-based CCM policies can reduce conflict through efforts at minimal transformation of local livelihoods, maximal attention to the tenure rights, responsibilities, and authority of citizens, and by improving, not degrading, the project landscapes. The paper presents the circumstances under which these guidelines are sidestepped by the A/R project, and importantly reveals that dramatic forest and livelihood transformation had already affected the community and environment in the REDD+ project site. There are deep contradictions at the heart of climate change policies toward which attention must be given, lest we leave our future generations with nothing but forest islands and castaway communities.

Description: Compressive principal component pursuit (CPCP) recovers a target matrix that is a superposition of low-complexity structures from a small set of linear measurements. Pervious works mainly focus on the analysis of the existence and uniqueness. In this paper, we address its stability. We prove that the solution to the related convex programming of CPCP gives an estimate that is stable to small entry-wise noise. We also provide numerical simulation results to support our result. Numerical results show that the solution to the related convex program is stable to small entry-wise noise under board condition.

Description: Control of gene regulatory networks is one of the fundamental topics in systems biology. In the last decade, control theory of Boolean networks (BNs), which is well known as a model of gene regulatory networks, has been widely studied. In this review paper, our previously proposed methods on optimal control of probabilistic Boolean networks (PBNs) are introduced. First, the outline of PBNs is explained. Next, an optimal control method using polynomial optimization is explained. The finite-time optimal control problem is reduced to a polynomial optimization problem. Furthermore, another finite-time optimal control problem, which can be reduced to an integer programming problem, is also explained.

Description: Land use without adequate soil erosion control measures is continuously increasing the  risk of soil erosion by water mainly in developing tropical countries. These countries are prone to  environmental disturbance due to high population growth and high rainfall intensity. The aim of  this study is to assess the state of soil erosion by water in Uganda at national and district levels, for  various land cover and land use (LCLU) types, in protected areas as well to predict the impact of  support practices on soil loss reduction. Predictions obtained using the Revised Universal Soil Loss  Equation (RUSLE) model indicated that the mean rate of soil loss risk in Uganda’s erosion‐prone  lands was 3.2 t∙ha−1∙y−1, resulting in a total annual soil loss of about 62 million tons in 2014. About  39% of the country’s erosion‐prone lands were comprised of unsustainable mean soil loss rates >1  t∙ha−1∙y−1. Out of 112 districts in Uganda, 66 districts were found to have unsustainable estimated  soil loss rates >1 t∙ha−1∙y−1. Six districts in Uganda were found to have mean annual soil loss rates of  >10 t∙ha−1∙y−1: Bududa (46.3 t∙ha−1∙y−1), Kasese (37.5 t∙ha−1∙y−1), Bundibugyo (28.9 t∙ha−1∙y−1), Bulambuli  (20.9 t∙ha−1∙y−1), Sironko (14.6 t∙ha−1∙y−1) and Kotido (12.5 t∙ha−1∙y−1). Among the LCLU types, the  highest soil loss rates of 11 t∙ha−1∙y−1 and 10.6 t∙ha−1∙y−1 were found in moderate natural forest and  dense natural forest, respectively, mainly due to their locations in highland areas characterized by  steep slopes ranging between 16% to 21% and their high rainfall intensity, ranging from 1255  mm∙y−1 to 1292 mm∙y−1. Only five protected areas in Uganda were found to have high mean  estimated mean soil loss rates >10 t∙ha−1∙y−1: Rwenzori Mountains (142.94 t∙ha−1∙y−1), Mount Elgon  (33.81 t∙ha−1∙y−1), Bokora corridor (12.13 t∙ha−1∙y−1), Matheniko (10.39 t∙ha−1∙y−1), and Nangolibwel  (10.33 t∙ha−1∙y−1). To manage soil erosion in Uganda’s protected areas, there is an urgent need to  control wildfires and human‐induced disturbances such as timber harvesting and soil compaction  from  domestic  animals.  Our  study  analysis  revealed  that  well‐established  terraces  and  strip‐cropping could significantly reduce soil loss rates in Uganda’s croplands by 80% (from 1.5  t∙ha−1∙y−1 to 0.3 t∙ha−1∙y−1) and by 47% (from 1.5 t∙ha−1∙y−1 to 0.8 t∙ha−1∙y−1), respectively, well below the  sustainable soil erosion tolerance rate (1 t∙ha−1∙y−1) for land and water conservation.

Description: Many studies have outlined the benefits for growth and reproduction resulting from thinning extremely crowded young forests regenerating after stand replacing wildfires (“thickets”). However, scarce information is available on how thinning may influence fire severity and vegetation regeneration in case a new fire occurs. We investigated the relationship between thinning and fire severity in P. halepensis thickets, and the effects on the establishment of pine seedlings and resprouting vigour in resprouter species the year after the fire. Our results show a positive relationship between forest basal area and fire severity, and thus reserved pines in thinned stands suffered less fire damage than those in un‐thinned sites (respectively, 2.02 ± 0.13 vs. 2.93 ± 0.15 in a scale from 0 to 4). Ultimately, differences in fire severity influenced post‐fire regeneration. Resprouting vigour varied depending on the species and the size of individuals but it was consistently higher in thinned stands. Concerning P. halepensis, the proportion of cones surviving the fire decreased with fire severity. However, this could not compensate the much lower pine density in thinned stands and thus the overall seed crop was higher in un‐thinned areas. Establishment of pine seedlings was negatively affected by the slope and positively driven by the number of cones and thus it was higher in un‐thinned than in thinned stands (respectively, 2581 ± 649 vs. 898 ± 325 seedlings∙ha-1). Thinning decreases fire intensity, and thus it may facilitate fire suppression tasks, but retaining a higher density of pines would be necessary to ensure P. halepensis regeneration after a new fire event.

Description: In defining the environmental preferences of plant species, statistical models are part of the essential tools in the field of modern ecology. However, conventional linear models require compliance with some parametric assumptions and if these requirements are not met, imply a serious limitation of the applied model. In this study, the effectiveness of linear and nonlinear generalized models was examined to identify the unitary effect of the principal environmental variables on the abundance of three tree species growing in the natural temperate forests of Oaxaca, Mexico. The covariates that showed a significant effect on the distribution of tree species were the maximum and minimum temperatures and the precipitation during specific periods. Results suggest that the generalized models, particularly smoothed models, were able to detect the increase or decrease of the abundance against changes in an environmental variable; they also revealed the inflection of the regression. In addition, these models allow partial characterization of the realized niche of a given species according to some specific variables, regardless of the type of relationship.

Description: Driven by various initiatives and international policy processes, the concept of Forest Landscape Restoration, is globally receiving renewed attention. It is seen internationally and in national contexts as a means for improving resilience of land and communities in the face of increasing environmental degradation through different forest activities. Ethiopia has made a strong voluntary commitment in the context of the Bonn Challenge—it seeks to implement Forest Landscape Restoration (FLR) on 15 million ha. In the context of rural Ethiopia, forest establishment and restoration provide a promising approach to reverse the widespread land degradation, which is exacerbated by climate change and food insecurity. This paper presents an empirical case study of FLR opportunities in the Amhara National Regional State, Ethiopia’s largest spans of degraded and barren lands. Following the Restoration Opportunity Assessment Methodology, the study categorizes the main types of landscapes requiring restoration, identifies and prioritizes respective FLR options, and details the costs and benefits associated with each of the five most significant opportunities: medium to large‐scale afforestation and reforestation activities on deforested or degraded marginal land not suitable for agriculture, the introduction of participatory forest management, sustainable woodland management combined with value chain investments, restoration of afro‐alpine and sub‐afro‐alpine areas and the establishment of woodlots.

Description: Forestry is an effective strategy for climate change mitigation. However, forestry activities not only sequester carbon but also release CO2. It is therefore important to formulate carbon subsidy and carbon taxation policies on the basis of the price of carbon. In this study, a forestry-based Computable General Equilibrium (CGE) model was built by using input-output data of China in 2014 to construct a Social Accounting Matrix (SAM). The model simulates different carbon price scenarios and was used to explore the effects of carbon subsidy and carbon taxation policies on the forestry economy. The main results can be summarized as follows: When the carbon price is low, the implementation of the policy increases forestry output and causes forest product prices to rise. When the carbon price is high, the carbon tax will produce an inhibitory effect, and output and prices will decline. With the constant rise of the carbon price, value addition will decrease, with flow to other industries. For the carbon sequestration policy, there is a reasonable carbon price range bound. In light of these results, relevant policies are proposed.

Description: In this paper, to overcome the innate drawbacks of some old methods, we present a new quintic spline method for integro interpolation. The method is free of any exact end conditions, and it can reconstruct a function and its first order to fifth order derivatives with high accuracy by only using the given integral values of the original function. The approximation properties of the obtained integro quintic spline are well studied and examined. The theoretical analysis and the numerical tests show that the new method is very effective for integro interpolation.

Description: Reduced Emissions from Deforestation and Forest Degradation (REDD+) has been systematically advanced within the UN Framework Convention on Climate Change (UNFCCC). However, implementing REDD+ in a populated landscape requires information on local costs and acceptability of changed practices. To supply such information, many studies have adopted approaches that explore the opportunity cost of maintaining land as forest rather than converting it to agricultural uses. These approaches typically assume that the costs to the smallholder are borne exclusively through the loss or gain of the production values associated with specific categories of land use. However, evaluating the value of land to smallholders in incomplete and messy institutional and economic contexts entails other considerations, such as varying portfolios of land holdings, tenure arrangements, restricted access to capital, and unreliable food markets. We suggest that contingent valuation (CV) methods may provide a more complete reflection of the viability of REDD+ in multiple-use landscapes than do opportunity cost approaches. The CV approach eliminates the need to assume a homogenous smallholder, and instead assumes heterogeneity around social, economic and institutional contexts. We apply this approach in a southern rural Cameroonian context, through the lens of a hypothetical REDD+ contract. Our findings suggest local costs of REDD+ contracts to be higher and much more variable than opportunity cost estimates.

Description: (1) Elevated atmospheric CO2 (eCO2) may affect organic inputs to woodland soils with potential consequences for C dynamics and associated aggregation; (2) The Bangor Free Air Concentration Enrichment experiment compared ambient (330 ppmv) and elevated (550 ppmv) CO2 regimes over four growing seasons (2005–2008) under Alnus glutinosa, Betula pendula and Fagus sylvatica. Litter from the experiment (autumn 2008) and Lumbricus terrestris were added to mesocosm soils. Microbial properties and aggregate stability were investigated in soil and earthworm casts. Soils taken from the field experiment in spring 2009 were also investigated; (3) eCO2 litter had lower N and higher C:N ratios. F. sylvatica and B. pendula litter had lower N and P than A. glutinosa; F. sylvatica had higher cellulose. In mesocosms, eCO2 litter decreased respiration, mineralization constant (respired C:total organic C) and soluble carbon in soil but not earthworm casts; microbial‐C and fungal hyphal length differed by species (A. glutinosa = B. pendula > F. sylvatica) not CO2 regime. eCO2 increased respiration in field aggregates but increased stability only under F. sylvatica; (4) Lower litter quality under eCO2 may restrict its initial decomposition, affecting C stabilization in aggregates. Later resistant materials may support microbial activity and increase aggregate stability. In woodland, C and soil aggregation dynamics may alter under eCO2, but outcomes may be influenced by tree species and earthworm activity.

Description: Structure from Motion (SfM) photogrammetry applied to photographs captured from Unmanned Aerial Vehicle (UAV) platforms is increasingly being utilised for a wide range of applications including structural characterisation of forests. The aim of this study was to undertake a first evaluation of whether SfM from UAVs has potential as a low cost method for forest monitoring within developing countries in the context of Reducing Emissions from Deforestation and forest Degradation (REDD+). The project evaluated SfM horizontal and vertical accuracy for measuring the height of individual trees. Aerial image data were collected for two test sites; Meshaw (Devon, UK) and Dryden (Scotland, UK) using a Quest QPOD fixed wing UAV and DJI Phantom 2 quadcopter UAV, respectively. Comparisons were made between SfM and airborne LiDAR point clouds and surface models at the Meshaw site, while at Dryden, SfM tree heights were compared to ground measured tree heights. Results obtained showed a strong correlation between SfM and LiDAR digital surface models (R2 = 0.89) and canopy height models (R2 = 0.75). However, at Dryden, a poor correlation was observed between SfM tree heights and ground measured heights (R2 = 0.19). The poor results at Dryden were explained by the fact that the forest plot had a closed canopy structure such that SfM failed to generate enough below-canopy ground points. Finally, an evaluation of UAV surveying methods was also undertaken to determine their usefulness and cost-effectiveness for plot-level forest monitoring. The study concluded that although SfM from UAVs performs poorly in closed canopies, it can still provide a low cost solution in those developing countries where forests have sparse canopy cover (〈50%) with individual tree crowns and ground surfaces well-captured by SfM photogrammetry. Since more than half of the forest covered areas of the world have canopy cover 〈50%, we can conclude that SfM has enormous potential for forest mapping in developing countries.

Description: Reducing Emissions from Deforestation and Forest Degradation (REDD+) offers developing countries an opportunity to engage in global climate change mitigation through the sale of carbon credits for reforestation, avoided deforestation and forest conservation projects. Funding for REDD+ projects has increased in recent years and REDD+ projects have proliferated, but relatively few studies have, as yet, examined their implementation. Here, we present a synthesis of the challenges and lessons learned while implementing a REDD+ project in an Emberá community in Panama. Our case study, documented in four cycles of collaborative action research over 11 years, examines how local communities sought to reduce emissions from deforestation and benefit from carbon offset trading while improving local livelihoods. Through semi-structured interviews and participatory methods, we found that success with REDD+ hinges on broader issues than those widely discussed in the literature and in policy circles. Though economic incentives for participants and the equitable distribution of benefits remain important to project participants, our study finds that, in adapting REDD+ strategies to best suit community needs, the role of a support system for implementation (“bridging institutions”) and REDD+’s potential as a conflict resolution mechanism for tenure issues deserve more attention as key factors that contribute to meaningful participation in REDD+.

Description: Sentiment Analysis on Twitter Data is indeed a challenging problem due to the nature, diversity and volume of the data. People tend to express their feelings freely, which makes Twitter an ideal source for accumulating a vast amount of opinions towards a wide spectrum of topics. This amount of information offers huge potential and can be harnessed to receive the sentiment tendency towards these topics. However, since no one can invest an infinite amount of time to read through these tweets, an automated decision making approach is necessary. Nevertheless, most existing solutions are limited in centralized environments only. Thus, they can only process at most a few thousand tweets. Such a sample is not representative in order to define the sentiment polarity towards a topic due to the massive number of tweets published daily. In this work, we develop two systems: the first in the MapReduce and the second in the Apache Spark framework for programming with Big Data. The algorithm exploits all hashtags and emoticons inside a tweet, as sentiment labels, and proceeds to a classification method of diverse sentiment types in a parallel and distributed manner. Moreover, the sentiment analysis tool is based on Machine Learning methodologies alongside Natural Language Processing techniques and utilizes Apache Spark’s Machine learning library, MLlib. In order to address the nature of Big Data, we introduce some pre-processing steps for achieving better results in Sentiment Analysis as well as Bloom filters to compact the storage size of intermediate data and boost the performance of our algorithm. Finally, the proposed system was trained and validated with real data crawled by Twitter, and, through an extensive experimental evaluation, we prove that our solution is efficient, robust and scalable while confirming the quality of our sentiment identification.

Description: Sentiment analysis has played a primary role in text classification. It is an undoubted fact that some years ago, textual information was spreading in manageable rates; however, nowadays, such information has overcome even the most ambiguous expectations and constantly grows within seconds. It is therefore quite complex to cope with the vast amount of textual data particularly if we also take the incremental production speed into account. Social media, e-commerce, news articles, comments and opinions are broadcasted on a daily basis. A rational solution, in order to handle the abundance of data, would be to build automated information processing systems, for analyzing and extracting meaningful patterns from text. The present paper focuses on sentiment analysis applied in Greek texts. Thus far, there is no wide availability of natural language processing tools for Modern Greek. Hence, a thorough analysis of Greek, from the lexical to the syntactical level, is difficult to perform. This paper attempts a different approach, based on the proven capabilities of gradient boosting, a well-known technique for dealing with high-dimensional data. The main rationale is that since English has dominated the area of preprocessing tools and there are also quite reliable translation services, we could exploit them to transform Greek tokens into English, thus assuring the precision of the translation, since the translation of large texts is not always reliable and meaningful. The new feature set of English tokens is augmented with the original set of Greek, consequently producing a high dimensional dataset that poses certain difficulties for any traditional classifier. Accordingly, we apply gradient boosting machines, an ensemble algorithm that can learn with different loss functions providing the ability to work efficiently with high dimensional data. Moreover, for the task at hand, we deal with a class imbalance issues since the distribution of sentiments in real-world applications often displays issues of inequality. For example, in political forums or electronic discussions about immigration or religion, negative comments overwhelm the positive ones. The class imbalance problem was confronted using a hybrid technique that performs a variation of under-sampling the majority class and over-sampling the minority class, respectively. Experimental results, considering different settings, such as translation of tokens against translation of sentences, consideration of limited Greek text preprocessing and omission of the translation phase, demonstrated that the proposed gradient boosting framework can effectively cope with both high-dimensional and imbalanced datasets and performs significantly better than a plethora of traditional machine learning classification approaches in terms of precision and recall measures.

Description: With the rapid development of Internet, the traditional computing environment is making a big migration to the cloud-computing environment. However, cloud computing introduces a set of new security problems. Aiming at the virtual machine (VM) escape attack, we study the traditional attack model and attack scenarios in the cloud-computing environment. In addition, we propose an access control model that can prevent virtual machine escape (PVME) by adapting the BLP (Bell-La Padula) model (an access control model developed by D. Bell and J. LaPadula). Finally, the PVME model has been implemented on full virtualization architecture. The experimental results show that the PVME module can effectively prevent virtual machine escape while only incurring 4% to 8% time overhead.

Description: While differences in greenhouse gas (GHG) fluxes between ecosystems can be explained to a certain degree, variability of the same at the plot scale is still challenging. We investigated the spatial variability in soil-atmosphere fluxes of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) to find out what drives spatial variability on the plot scale. Measurements were carried out in a Scots pine (Pinus sylvestris L.) forest in a former floodplain on a 250 m2 plot, divided in homogenous strata of vegetation and soil texture. Soil gas fluxes were measured consecutively at 60 points along transects to cover the spatial variability. One permanent chamber was measured repeatedly to monitor temporal changes to soil gas fluxes. The observed patterns at this control chamber were used to standardize the gas fluxes to disentangle temporal variability from the spatial variability of measured GHG fluxes. Concurrent measurements of soil gas diffusivity allowed deriving in situ methanotrophic activity from the CH4 flux measurements. The soil emitted CO2 and consumed CH4 and N2O. Significantly different fluxes of CH4 and CO2 were found for the different soil-vegetation strata, but not for N2O. Soil CH4 consumption increased with soil gas diffusivity within similar strata supporting the hypothesis that CH4 consumption by soils is limited by the supply with atmospheric CH4. Methane consumption in the vegetation strata with dominant silty texture was higher at a given soil gas diffusivity than in the strata with sandy texture. The same pattern was observed for methanotrophic activity, indicating better habitats for methantrophs in silt. Methane consumption increased with soil respiration in all strata. Similarly, methanotrophic activity increased with soil respiration when the individual measurement locations were categorized into silt and sand based on the dominant soil texture, irrespective of the vegetation stratum. Thus, we suggest the rhizosphere and decomposing organic litter might represent or facilitate a preferred habitat for methanotrophic microbes, since rhizosphere and decomposing organic are the source of most of the soil respiration.