ALBERT

Beschreibung: This study considered airborne laser scanning (ALS) based aboveground biomass (AGB) prediction in mountain forests. The study area consisted of a long transect from southern Norway to northern parts of the country with wide ranges of elevation along a long latitudinal gradient (58°N–69°N). This transect was covered by ALS data and field data from 238 plots. AGB was modeled using different types of predictor variables, namely ALS metrics, variables related to growing conditions (elevation, latitude, and climatic variables), and tree species information. Modelling of AGB in the long transect covering diverse mountainous forest conditions was challenging: the RMSE values were rather large (37%–70%). The effects of growing conditions on model predictions were minor. However, species information was essential to improve accuracy. The analysis revealed that when doing inventories of spruce-dominated areas, all plots should be pooled together when the models are developed, whereas if pine or deciduous species dominate the area in question, separate dominant species-wise models should be constructed.

Beschreibung: As part of the development of the 2011 National Land Cover Database (NLCD) tree canopy cover layer, a pilot project was launched to test the use of high-resolution photography coupled with extensive ancillary data to map the distribution of tree canopy cover over four study regions in the conterminous US. Two stochastic modeling techniques, random forests (RF) and stochastic gradient boosting (SGB), are compared. The objectives of this study were first to explore the sensitivity of RF and SGB to choices in tuning parameters and, second, to compare the performance of the two final models by assessing the importance of, and interaction between, predictor variables, the global accuracy metrics derived from an independent test set, as well as the visual quality of the resultant maps of tree canopy cover. The predictive accuracy of RF and SGB was remarkably similar on all four of our pilot regions. In all four study regions, the independent test set mean squared error (MSE) was identical to three decimal places, with the largest difference in Kansas where RF gave an MSE of 0.0113 and SGB gave an MSE of 0.0117. With correlated predictor variables, SGB had a tendency to concentrate variable importance in fewer variables, whereas RF tended to spread importance among more variables. RF is simpler to implement than SGB, as RF has fewer parameters needing tuning and also was less sensitive to these parameters. As stochastic techniques, both RF and SGB introduce a new component of uncertainty: repeated model runs will potentially result in different final predictions. We demonstrate how RF allows the production of a spatially explicit map of this stochastic uncertainty of the final model.

Beschreibung: To better understand climatic origins of annual tree-growth anomalies in boreal forests, we analysed 895 black spruce (Picea mariana (Mill.) B.S.P.) tree-growth series from 46 xeric sites situated along three latitudinal transects in Eastern Canada. We identified interannual (based on comparison with previous year growth) and multidecadal (based on the entire tree-ring width distribution) growth anomalies between 1901 and 2001 at site and transect levels. Growth anomalies occurred mainly at site level and seldom at larger spatial scales. Both positive interannual and multidecadal growth anomalies were strongly associated with below-average temperatures and above-average precipitation during the previous growing season (Junet–1 – Augustt–1). The climatic signature of negative interannual and multidecadal growth anomalies was more complex and mainly associated with current-year climatic anomalies. Between the early and late 20th century, only negative multidecadal anomalies became more frequent. Our results highlight the role of previous growing season climate in controlling tree growth processes and suggest a positive association between climate warming and increases in the frequency of negative multidecadal growth anomalies. Projected climate change may further favour the occurrence of tree-growth anomalies and enhance the role of site conditions as modifiers of tree response to regional climate change.

Beschreibung: Wood ash may be an effective soil amendment in North America to restore acidified and low-nutrient forest soils, but little research exists beyond its effects on soil and plants. Eastern Red-backed Salamander (Plethodon cinereus (Green, 1818)) abundance was assessed in a northern hardwood forest 1 year following an ash-addition field trial. Plots were established with fly ash and bottom ash treatments of 0, 1, 4, and 8 Mg·ha−1 (n = 4), and cover boards were positioned both with and without ash beneath. One year following ash additions, salamander abundance had increased under boards with fly ash beneath, and bottom ash had no effect. Soil pH and electrical conductivity increased under cover boards with ash beneath them and for uncovered soil, and the effects were strongest under cover boards with ash beneath. The effects of ash were generally stronger at higher dosages, and fly ash was stronger than bottom ash. The moisture holding capacity of fly ash was 60% higher than the soil and was 63% lower than the soil for bottom ash, but they had little effect on moisture of the forest floor. These results suggest that ash altered salamander abundance via soil pH and moisture and would not inhibit salamander movement over the forest floor.

Beschreibung: Forest health deteriorated in eastern North America as a result of depletion of available soil base cations by elevated inputs of acid deposition. We experimentally restored available calcium (Ca) to soils of a forested watershed at Hubbard Brook, New Hampshire, and measured the response of fine root biomass 14 years after treatment. In this northern hardwood forest, fine root (

Beschreibung: Long-term forest inventories provide a unique opportunity to quantify changes in forest structure and evaluate how changes compare with current stand development models. An examination of a 70 year record at the Bartlett Experimental Forest, New Hampshire, indicated that although species abundances have primarily changed as expected under natural succession, some unexpected results were also detected. This included a significant decline in sugar maple (Acer saccharum Marsh.) abundance driven by reduced regeneration and increases in red spruce (Picea rubens Sarg.) at the expense of sympatric balsam fir (Abies balsamea (L.) Mill.) and hardwoods at upper elevations. In contrast with accepted stand development models, biomass continues to accrue on these mid- to late-successional forests. Importantly, biomass accumulated at even greater rates in recent decades compared with historical norms. These results support evidence that the anthropogenic influences of a changing climate and the legacy of acid deposition may be altering stand dynamics in northeastern forests.

Beschreibung: In this study, we tested the efficacy of establishing lodgepole pine (Pinus contorta Dougl.) from seed using woody mulch produced from slashed tree tops from a pine harvesting site; this mulch contained the closed serotinous cones of the lodgepole pine. Mulch was spread on prepared reclamation sites at depths of 0, 1, 3, and 5 cm. Broadcast seeding of pine was also done at mulch depths of 0 and 1 cm. Mulch cover that was 1 cm thick was the preferred treatment, as it produced 17 000 seedlings·ha−1 by the third year after treatment while being similar in seedling density to the 3 and 5 cm treatments. When 50 000 seeds·ha−1 were added, seedling density went up more on the sites with 1 cm of mulch than the sites with no mulch. Soil temperature was lower and temperature extremes were reduced under the mulch layer compared with the control plot. The plots with 1 cm of mulch also had higher soil moisture in the mineral layer than the plots with 0 cm of mulch. A thin layer of woody mulch, therefore, provided a source of pine seed and the covering of the ground provided a more benign environment for the establishment of pine germinants.

Beschreibung: In the future management and sustainable use of boreal forests, it is crucial to consider the rate and strength of tree responses to an elevated water table and the concurrent oxygen limitations, especially in peatlands. We examined the response dynamics of 7-year-old Scots pine (Pinus sylvestris L.) seedlings to a 5-week waterlogging (WL) treatment during a growing season in a root lab (dasotron) experiment. WL took place after shoot elongation had ended but while growth of the trunk diameter was still in progress. Trunk sap flow and needle water potential started to decrease immediately after the onset of WL, while the first signs in needle gas exchange — seen as decreases in the potential efficiency of photosystem II, the rates of light-saturated net assimilation and transpiration, and increased needle respiration — were observed after 3 weeks of WL. New needles responded to WL more strongly than the old ones. Drainage with consequent re-oxygenation of the soil caused a further decrease in sap flow. We conclude that through negative feedback on transpiration and net photosynthesis, WL during the growing season is harmful for Scots pine, leading to potential growth losses or even dying of trees within a few weeks of WL.

Beschreibung: Logging and burning of the resultant woody debris is a management tool to reduce fire risk. Burning of the debris as piles affects the underlying soil biota and soil physical and (or) chemical properties. The resulting disturbance created by the burns may create opportunities for the establishment and spread of non-native plant species. Here, we test three restoration treatments on recent, approximately 1-year-old, pile burn scars, including an arbuscular mycorrhizal fungal (AMF) inoculant (present or absent), a ground cover (straw or no straw added), and different seeding types (native seed mix, agronomic seed mix, and no seed). The most effective treatment in reducing undesired non-native species cover was the seeding of agronomic species; here “native” and “non-native” groups exclude sown agronomic species. Undesired non-native cover was 15.1% in plots with no seed, 9.1% in plots with native seed added, and 3.5% in plots with agronomic seed added. Total vegetation cover, mostly through the increase of agronomic species, was increased by seeding and by the application of straw cover. Commercial AMF inoculum was an ineffective treatment, suggesting that a better understanding of host specificity is warranted. Restoration efforts should be directed at burn scar sites after burning to ameliorate the effects of invasive species colonization, and the use of agronomic species may prevent non-native invasive plants from establishing.

Beschreibung: For a study area in the Brazilian state of Santa Catarina, the utilities of local and global forest maps in combination with poststratified and model-assisted estimators for increasing the precision of estimates of forest area were compared. Auxiliary information was in the form of local maps, the recent Global Forest Change map, and combinations of these maps. The poststratified estimators produced estimates of greater precision than the model-assisted regression estimators for maps of categorical variables, but the model assisted estimators produced estimates of greater precision for maps of continuous variables. The Global Forest Change map was the least accurate of all the maps, but it produced estimates of forest area that were similar to those for the other maps and that were more precise than if the map had not been used. Thus, the Global Forest Change map may be an attractive option if local maps are not available or cannot be constructed. The primary contributions of the study are two-fold. First, this is one of the first case studies that rigorously assess the utility of global maps for national estimation. After accumulation of a few more such studies, broader generalizations should be forthcoming. Second, a statistical basis is provided for the previously unexplained greater precision for poststratified estimators than for model-assisted estimators.

Beschreibung: In this paper, we evaluate the market and welfare effects of the 2006 United States (U.S.) – Canada Softwood Lumber Agreement (SLA 2006) based on a U.S. import demand model for Canadian softwood lumber. We find that SLA 2006 reduces the U.S. lumber imports from Canada by 7.78% in the months when export taxes took effect. The welfare analysis based on a partial equilibrium framework shows that U.S. lumber producers gained $1.6 billion and U.S. consumers lost $2.3 billion in 9 years under SLA 2006.

Beschreibung: In the southeastern United States, many forest managers are interested in restoring longleaf pine (Pinus palustris Mill.) to upland sites that currently support loblolly pine (Pinus taeda L.). We quantified the effects of four canopy treatments (uncut Control; MedBA, harvest to 9 m2·ha−1; LowBA, harvest to 5 m2·ha−1; and Clearcut) and three cultural treatments (NT, no treatment; H, herbicide release of longleaf pine seedlings; and H+F, herbicide release plus fertilization) on resource availability and growing conditions in relation to longleaf pine seedling response for 3 years. Harvesting treatments reduced competition from canopy trees but resulted in greater abundance of understory vegetation. Harvesting shifted the interception of light from the canopy to the subcanopy vegetation layer; however, total light availability at the forest floor increased with the intensity of canopy removal. Soil moisture was not affected by harvesting or by the cultural treatments. Foliar nutrient concentrations (N, P, and K) of longleaf pine seedlings generally increased with the intensity of the harvest treatment. Of the plant resources measured, we found that light was most strongly correlated with longleaf pine seedling growth and that incorporating the interception of light by subcanopy vegetation improved the relationship over that of canopy light transmittance alone.

Beschreibung: Conservation of Prunus padus L., a tree of high ecological and pharmacological importance, has been evaluated by storing seeds at subzero (−20 °C and −80 °C) and cryogenic (−196 °C) temperatures for various durations. The effect of the seed’s water content (WC) ranging from 3.5% to 21.1%, fresh weight basis, and the effect of cooling and rewarming procedures on seed viability was investigated. Emergence of seedlings was observed for 40%–55% of the noncryopreserved seeds, with no significant effect of WC. The same seedling emergence was recorded for seeds cryopreserved by direct immersion in liquid nitrogen within the WC range of 3.5%–15.0%. Seeds rehydrated above 17% WC were unable to tolerate cryopreservation. Seedling emergence was not affected by cooling regime but decreased by 10% after stepwise rewarming compared with rapid rewarming in a water bath or on air. No reduction in seedling emergence was recorded after storage at −20 °C, −80 °C, and −196 °C for 1 h, 1 week, and 1 month. We recommend seed storage at subzero or cryogenic temperatures as an effective conservation option for P. padus and possibly other Prunus species. We also demonstrated high effectiveness and reliability of Bayesian statistical methods for analyzing binomial data such as the data obtained in seed conservation experiments.

Beschreibung: The fragmentation and loss of old-growth forest has led to the decline of many forest-dwelling species that depend on old-growth forest as habitat. Emblematic of this issue in many areas of the managed boreal forest in Canada is the threatened woodland caribou (Rangifer tarandus caribou (Gmelin, 1788)). We develop a methodology to help determine when and how timber can be harvested to best satisfy both industrial timber supply and woodland caribou habitat requirements. To start, we use least-cost paths based on graph theory to determine the configuration of woodland caribou preferred habitat patches. We then developed a heuristic procedure to schedule timber harvesting based on a trade-off between merchantable wood volume and the remaining amount of habitat and its connectivity during a planning cycle. Our heuristic can attain 84% of the potential woodland caribou habitat that would be available in the absence of harvesting at the end of a 100 year planning horizon. Interestingly, this is more than that which is attained by the current plan (50%) and a harvesting plan that targets high volume stands (32%). Our results indicate that our heuristic procedure (i.e., an ecologically tuned optimization approach) may better direct industrial activities to improve old-growth habitat while maintaining specified timber production levels.

Beschreibung: Survey sampling with model-assisted estimation has been gaining popularity in forest inventory recently, as the availability of cheap, good-quality remotely sensed data that can be used as auxiliary information has improved. Most of the studies have been carried out using parametric (linear or nonlinear) models. However, nonparametric and semiparametric models such as k nearest neighbor, kernel, and generalized additive are widely used in forest inventory. The results are usually calculated using the difference estimator (i.e., assuming an external model), even though the models used are based on the sample (i.e., an internal model). In that case, variances will likely be underestimated. In this study, we analyze how well the difference estimator works for different types of models, both internal and external. The study is based on simulated populations produced using a C-vine copula model with empirical marginals. The external model is based on real data, and the internal models are estimated from samples from the simulated population. The results show that the analytical variance estimates for a difference estimator based on an overfitted kernel model can seriously underestimate the true variance.

Beschreibung: We used six metrics of size and growth variation (standard deviation (SD), coefficient of variation (CV), skewness coefficient (S), Gini coefficient (G), Lorenz asymmetry coefficient (LAC), and growth dominance coefficient (GD)) to describe changes in two long-term ponderosa pine (Pinus ponderosa Douglas ex P. Lawson & C. Lawson) initial spacing trials in Oregon and Washington, USA. Trends were examined over a 35-year time period and across a range of initial stand densities (from 154 to 2470 trees·ha−1) for four measures of tree size: diameter at breast height (dbh, 1.37 m), basal area (BA), height, and volume. Unlike many previous studies of size variation in monospecific stands, our results suggest that variation declined or remained relatively stable for all treatments at both study areas. This suggests that these stands are experiencing size symmetric competition for belowground resources. We found that a combination of metrics is necessary to provide a complete picture of size variability and differentiation in developing stands. We recommend using the CV or G, as there were clear trends with increasing density for all size variables. If the objective of the assessment was to track changes in absolute size within an individual stand, we would recommend using the SD, as there were consistent trends with time for all size variables. S, LAC, and GD may be less suited for comparing differentiation during the early stages of stand development because of a lack of clear trends with stand density and time.

Beschreibung: Understanding vegetation recovery patterns following wildfire and logging disturbance is essential for long-term planning in sustainable forestry. Plot-scale studies indicate differences in revegetation rates and postdisturbance composition in Labrador, Canada, following fire in comparison with harvest but do not necessarily capture the full range of relevant landscape variability. Using a satellite-based land cover classification that distinguishes forest, woodland, shrub, lichen, and bare ground, we applied partial least-squared regression (PLS) to derive empirical models of vegetation dynamics following fire and harvest. Forest recovery rates were found to be generally slow and sensitive to predisturbance land condition and site quality (potential productivity). We found that, although disturbance type was not specifically retained in the model, estimated rates of vegetation recovery were faster for a typical harvest compared with a typical fire (i.e., 50% recovery at 14 years versus 33 years, respectively). Indeed, the model predicts important regeneration delay following fire that appears sensitive to both site quality and area burned. Understanding factors affecting broad-scale vegetation recovery relationships can help guide future sustainable forestry and wildlife habitat initiatives in the region, in part by parameterizing landscape simulation models used for strategic decision support.

Beschreibung: The planning of wood procurement requires reliable information about the species-specific timber assortments on which the economic value of a production forest depends. The timber assortments refer to the stem volumes of the sawlog and pulpwood fractions, specified in terms of both timber quality and allowable log dimensions, e.g., the stem diameter at breast height (dbh). We propose here an airborne laser scanning based calibration framework for generating species-specific dbh distributions that combines the area-based approach (ABA) and individual-tree detection (ITD), two established and independent approaches for retrieving forest attributes from airborne laser scanning data. Both ABA- and ITD-derived dbh distributions were generated nonparametrically for pine, spruce, coniferous, deciduous, and all species and assessed with respect to the plot-level species-specific total stem volume (m3·ha–1) and approximations of volume of timber assortments. Although after calibration, the total volume of all species and the volume approximations of coniferous sawlog and spruce pulpwood decreased in accuracy by 4%–7%, the calibration improved the accuracy of the other 12 species-specific estimates by 2%–17%, testifying to the general effectiveness of the proposed calibration framework.

Beschreibung: The present study aims to develop biologically sound and parsimonious site index models for Norway to predict changes in site index (SI) under different climatic conditions. The models are constructed using data from the Norwegian National Forest Inventory and climate data from the Norwegian meteorological institute. Site index was modeled using the potential modifier functional form, with a potential component (POT) depending on site quality classes and two modifier components (MOD): temperature and moisture. Each of these modifiers was based on a portfolio of candidate variables. The best model for spruce-dominated stands included temperature as modifier (R2= 0.56). In the case of pine- and deciduous-dominated stands, the best models included both modifiers (R2= 0.40 and 0.54 for temperature and moisture, respectively). We illustrate the use of the models by analyzing the possible shift in SI for year 2100 under one (RCP4.5) of the benchmark scenarios adopted by the Intergovernmental Panel on Climate Change for its fifth assessment report. The models presented can be valuable for evaluating the effect of climate change scenarios in Norwegian forests.

Beschreibung: Black spruce (Picea mariana (Mill.) B.S.P.) is a dominant species on north-facing slopes located on the permafrost in the Alaskan Interior, where tree growth rates vary significantly across slope gradients. To better understand the effects of nitrogen (N) and mycorrhizal associations on plant growth, we investigated the relationships between tree growth and isotope ratios of nitrogen (δ15N) in foliage and roots, because plant δ15N values reflect tree dependencies on N uptake by mycorrhizae. We established two transects (one along a slope gradient, and a second on a north-to-east axis at a fixed elevation) and four plots on the slope gradient transect. We measured current shoot growth of saplings on transects and aboveground biomass (AGB) in the plots. We collected foliage and fine root samples and measured their δ15N signatures and N concentrations. The AGB and shoot growth varied widely across the gradient: values were higher at high elevations and at the east–northeast aspect. Foliage δ15N values and N concentrations were positively correlated with tree growth, but growth rate was negatively correlated with the dependency on mycorrhizae for N uptake. Thus, black spruce had a reduced dependency on mycorrhizae for N uptake on the upper slope, where conditions were N-rich. On the lower slope, where the soil active layer was shallow, black spruce growth was limited and had an elevated dependency on mycorrhizae for N uptake.

Beschreibung: Ecosystem-based management advocates that forestry disturbances should aim to emulate natural disturbances to mitigate the landscape-level impact of forest management. This study compares the impact of clear-cuts followed by a prescribed burn (CCPB) with clear-cuts alone (CC) and current careful logging practices (CLAAG: “careful logging around advanced growth”) on understory composition within black spruce (Picea mariana Miller (BSP)) paludified forest stands at the plot, site, and treatment levels using a functional-type approach. Vascular and nonvascular taxa showed significant differences in composition at the plot level among treatments. We found that pioneer taxa occurred mainly in CCPB sites, while late-successional taxa characterized CC sites. CLAAG sites had higher taxa richness than CCPB and CC sites, and we found that CCPB treatments were most likely to promote vascular taxa compositions that are more similar to those observed after natural disturbances. Additionally, the relative abundance of Sphagnum spp., responsible for paludification, was significantly reduced in sites treated by prescribed burning. This study therefore presents results suggesting that prescribed burning might represent a sustainable alternative to current harvesting techniques in the Clay Belt of eastern Canada that could help in preserving biodiversity (in terms of understory species assemblage) while maintaining or even enhancing forest productivity.

Beschreibung: Mixed-species stands are on the advance in Europe. They fulfil many functions better than monocultures. Recent papers show that mixed stands can have higher yields, but it remains open whether mixed stands simply grow faster along the same self-thinning lines as pure stands or have higher maximum stand densities. We analyzed the effect of species mixing on maximum density based on triplets of pure and mixed stands at approximately maximum density. Most considered mixtures include Norway spruce (Picea abies (L.) H. Karst.). We show that (i) in mixed stands, maximum density is, on average, 16.5% higher than in neighbouring pure stands, and (ii) species mixtures with Norway spruce exceed densities of pure stands by 8.8%, on average. For individual species mixtures, we find a significant density effect of +29.1% for Norway spruce mixed with European larch (Larix decidua Mill.) and +35.9% for Scots pine (Pinus sylvestris L.) in association with European beech (Fagus sylvatica L.). No significant links with stand variables such as age and mean tree size and site fertility were found. The results indicate that species mixing substantially increases stand density, indicating a higher carrying capacity caused by a higher supply and use efficiency of resources. The implications for inventory, silviculture, and forest modelling are discussed.

Beschreibung: Optimization models on continuous cover forestry are complicated and typically incompatible with rotation models. This dichotomy is theoretically unsatisfactory and makes the choice between clearcuts and continuous cover forestry vague. We present a theoretically sound and empirically detailed generalized setup with an optimal clear-cut regime (or even-aged management) and optimal continuous cover regime (or uneven-aged management) as special cases. It includes a size-structured growth model, variable and fixed harvesting costs, and allows for the completely flexible optimization of harvest timing in both regimes. Flexible harvest timing becomes essential when optimizing the transition from clear-cut regimes toward continuous cover forestry. The model is applied to Norway spruce (Picea abies (L.) Karst.) and solved as a dynamic mixed-integer problem. Low or moderate site productivity, an interest rate above 2%, and a high artificial regeneration cost support the optimality of continuous cover forestry. In its most general form, the optimal clear-cut regime does not exist when the continuous cover regime is globally optimal, and when it exists, the rotation period lengthens with interest rate. The optimal choice between forest management regimes may depend on the initial stand state and whether the naturally regenerated seedlings are utilized in solutions with clearcuts. Maximizing sustainable yield favors clearcuts.

Beschreibung: This paper explores the ecosystem services associated with woodlands, as they are viewed by individuals in Scotland, with the idea to reconcile objectives for multifunctionality with the legacy of past forestry systems that were not designed with multifunctionality in mind. Research follows a semi-qualitative route and applies the Q method to identify and explain a range of attitudes among the general public and forestry-associated stakeholders regarding the functional future of forestry in Scotland. Four distinctive groups of attitudes were identified and key factors influencing the attitudinal diversity were explained. Despite the uncovered attitudinal heterogeneity, all groups of attitudes have strong emphasis on native woodland regeneration and on improvement of aesthetic values of woodlands but differ concerning afforestation. An improved understanding of what people think provided an indication of their recognition of ecosystem services types and the trade-offs between these, opportunities available, and factors that can hamper forestry development (e.g., concerning the aspiration of increasing Scotland’s forest cover to 25%). Findings suggest that the productivists’ position (for which the economic objectives are important) remains strong in Scotland. Results (compared with those in several other countries) demonstrate comparability between public and stakeholder perspectives in support of the multifunctional forestry, and this has distinct policy relevance and implications for decision-making.

Beschreibung: Understanding variation in tree stem form is fundamental to both ecological and economic assessments of forest ecosystem structure and function. Stem taper models (STMs) are widely used to describe tree form, but it can be challenging to apply them to trees with stems that diverge from an idealized norm, often leading to the exclusion of many trees from stem taper studies. Here, new “whole-tree” form type classes are advanced as simple and useful groupings for capturing stem form variation of trees of diverse morphological types and tested with a large tree data set without exclusion criteria. New form type classes explained much more of main stem form variation than knowledge of tree species, while “merchantable” form types explained the most variation between trees and stands. Broad-leaved species were much more likely to have complex stem forms than needle-leaved species, but species “evergreenness” was a very weak predictor of stem form variation when tree- and stand-level form variation was accounted for. A new, generalized framework for stem taper modeling is demonstrated, using both species and merchantable form types to capture tree-level random effects. New form types and the STM approach are relatively easy to apply and should be relatively simple to integrate into any conventional forest inventory system. Overall, the study demonstrates the importance of including and accounting for the diversity of observed stem forms in developing STMs.

Beschreibung: Estimating aboveground biomass and its components requires sound statistical formulation and evaluation. Using data collected from 55 destructively sampled trees in different parts of Oregon, we evaluated the performance of three groups of methods to estimate total aboveground biomass and (or) its components based on the bias and root mean squared error (RMSE) that they produced. The first group of methods used an analytical approach to estimate total and component biomass using existing equations and produced biased estimates for our dataset. The second group of methods used a system of equations fitted with seemingly unrelated regression (SUR) and were superior to the first group of methods in terms of bias and RMSE. The third group of methods predicted the proportion of biomass in each component using beta regression, Dirichlet regression, and multinomial log-linear regression. The predicted proportions were then applied to the total aboveground biomass to obtain the amount of biomass in each component. The multinomial log-linear regression approach consistently produced smaller RMSEs compared with both SUR methods. The beta and Dirichlet regressions were superior to both SUR methods except for Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) branch biomass, for which the simple SUR method produced smaller RMSE compared with the beta and Dirichlet regressions.

Beschreibung: Maritime pine (Pinus pinaster Aiton) forests in the Aquitaine region, southwestern France, suffered catastrophic damage from storms Martin (1999) and Klaus (2009), and more damage is expected in the future due to forest structural change and climate change. Thus, developing risk assessment methods is one of the keys to finding forest management strategies to reduce future damage. In this paper, we evaluated two approaches to calculate wind damage risk to individual trees using data from different damage data sets from two storm events. Airflow models were coupled either with a mechanistic model (GALES) or a bias-reduced logistic regression model to discriminate between damaged and undamaged trees. The mechanistic approach was found to successfully discriminate the trees for different storms but only in locations with soil conditions similar to where the model parameters were obtained from previous field experiments. The statistical approach successfully discriminated the trees only when applied to similar data as that used for creating the models, but it did not work at an acceptable level for other data sets. One variable, decade of stand establishment, was a significant variable in all statistical models, suggesting that site preparation and tree establishment could be a key factor related to wind damage in this region.

Beschreibung: Temperate forests in northeastern China play a key role in the national carbon (C) budget; however, this role has been poorly quantified. The objective of this study was to quantify C storage, net primary production (NPP), and net ecosystem production (NEP) in four major temperate forest types in northeastern China. The four forest types include a primary mixed broadleaf – Korean pine (Pinus koraiensis Siebold & Zucc.) old-growth forest and three mid-aged regenerating forests, i.e., a secondary birch (Betula platyphylla Sukaczev) forest, a Korean pine plantation, and a Dahurian larch (Larix gmelinii (Rupr.) Rupr.) plantation. Total C storage differed significantly among the four forest types, with the highest storage (315.4 t C·ha−1) in the old-growth forest. Soil organic C accounted for 55%–70% of the ecosystem C, whereas vegetation C accounted for 28%–43% of the ecosystem C. Soil organic C storage in the two plantations was significantly lower than that in old-growth and secondary birch forests. The allocation (aboveground and belowground) of NPP, but not the total NPP, differed significantly among the forest types. Litterfall (44%–60%) and fine root production (43%–47%) contributed the largest proportion of the aboveground and belowground NPP, respectively. The highest NEP was in the Korean pine plantation (328.0 g C·m−2·year−1), followed by the old-growth (311.9 g C·m−2·year−1) and secondary birch (231.1 g C·m−2·year−1) forests, with the lowest NEP in the Dahurian larch plantation (187.9 g C·m−2·year−1). These results suggest that the major forest types are currently C sinks and Korean pine plantation establishment can be a promising approach for increasing C sequestration in northeastern China.

Beschreibung: Highly variable patterns of seed production (“masting”) have been hypothesized to be driven by internal dynamics of resource storage and depletion. This hypothesis predicts that if seed production is artificially reduced, then the availability of unused stored resources should result in subsequent enhancement of the seed crop. We tested this prediction in two oak species with contrasting patterns of annual seed production (highly variable and relatively constant) by means of controlled burns at various frequencies over a 17-year period. We found that controlled burns reduced acorn production by both species in the year of the burn. In the species with relatively constant productivity, acorn production returned to baseline levels in the year following a burn; however, in the species with highly variable productivity, acorn production significantly increased the year following a burn. These results support a key prediction of the stored resource hypothesis by means of a long-term experimental test in wild tree populations.

Beschreibung: This paper investigates the practices of the value-added wood products industry in British Columbia (BC) with respect to innovativeness using the results of an online survey. The survey employed an indirect self-evaluation scale to assess the propensity to create and (or) adopt new products, processes, and business systems. Using chain of custody certification as an example of business systems innovation, this study also investigated the attitudes of the value-added wood products manufacturers, who were already certified or who may become certified, towards innovation in this form. Results show that the respondents rated themselves as more innovative with respect to business systems innovation compared with product and process innovations. Overall, innovation levels were low in the BC value-added wood products sector, a result which was confirmed in the case of chain of custody certification.

Beschreibung: Dead wood pools are strongly influenced by natural disturbance events, stand development processes, and forest management activities. However, the relative importance of these influences can vary over time. In this study, we evaluate the role of these factors on dead wood biomass pools across several forest management alternatives after 60 years of treatment on the Penobscot Experimental Forest in central Maine, USA. After accounting for variation in site quality, we found significant differences in observed downed coarse woody material (CWM; ≥7.6 cm small-end diameter) and standing dead wood biomass among selection, shelterwood, and commercial clear-cut treatments. Overall, total dead wood biomass was positively correlated with live tree biomass and was negatively correlated with the average wood density of nonharvest mortality. We also developed an index of cumulative harvest severity, which can be used to evaluate forest attributes when multiple harvests have occurred within the same stand over time. Findings of this study highlight the dynamic roles of forest management, stand development, and site quality in influencing dead wood biomass pools at the stand level and underscore the potential for various outcomes from the same forest management treatment applied at different times in contrasting stands.

Beschreibung: Mixed and multi-layered forest ecosystems are sometimes more productive than monospecific and single-layered ones. It has been suggested that trees of different species and sizes occupy complementary positions in space, which would act as a mechanism to increase canopy light interception and wood production. However, greater canopy light interception reduces the average amount and variability of transmitted radiation, offering fewer opportunities for all species to regenerate and to maintain forest heterogeneity in the long run. We investigated whether increasing overstory heterogeneity indeed results in greater canopy light interception and lower variability in transmittance. We modeled the three-dimensional structure of forest stands with three typical forest structures, 10 mixtures of four tree species, and three different basal areas. We used the forest light interception model SamsaraLight and performed three-way analyses of covariance to analyze the effects of the three varied components of forest heterogeneity. We found no evidence that increasing structural heterogeneity increases canopy light interception. However, the light interception by mixed canopies was greater than the weighted average of light interception by the corresponding pure canopies. Variability in transmittance increased in some cases with compositional heterogeneity and, to a lesser extent, with tree size inequalities. The advantage of heterogeneous forests is in opportunities for natural regeneration, as well as in opportunities to enhance canopy light interception.

Beschreibung: Which regions contribute most to national growth? Do large cities ‘need’ more expenditure per capita? The relation between these two questions is the subject of a current German discussion, but it is of importance for other countries as well. What precisely is the issue? The substantial German fiscal equalization systems between states (Länder) and between communities assign estimates of higher expenditure need per capita to larger cities. This paper argues that this is justified, because, following the arguments of new regional economics, the modern agglomerations are of crucial importance for national growth. To maintain this role they have to be able to keep or receive enough public finance. To assess this, total public flows out of and into regions have to be taken into account. The relevant analysis shows that their contribution to upperlevel (federal and Länder) finances is far above average, but that they receive relatively little from federal and Länder spending; consequently they experience large net fiscal outflows. The use of the abovementioned progressive scale of expenditure need in the equalization systems reduces this fiscal siphoning-off, at least to some extent.

Beschreibung: Zusammenfassung Der Beitrag untersucht die Pendeldistanzen und die Dauer der Pendelwege im Kontext von Randwanderung und Geschlechterverhältnissen im Umland der Stadt Hagen (Westfalen). Die Ergebnisse zeigen, dass auch innerregionale Wanderungen häufig mit beruflichen Motiven verbunden sind. Die geschlechtsspezifischen Veränderungen im Pendeln nach dem Umzug sprechen für die Orientierung des Wohnstandorts am Arbeitsplatz des Mannes, wobei Frauen tendenziell die „Trailing-wife“-Position einnehmen. Darüber hinaus gehen die Wanderungen mit dem Versuch einer Begrenzung oder Verkürzung der Pendelwege auf der Haushaltsebene einher. Dies drückt sich nicht nur in der Pendeldauer aus, sondern auch in der räumlichen Konfiguration von Wohnen und Arbeiten bei erwerbstätigen Paaren, die hier über die relative Lage von Wohn- und Arbeitsorten zueinander abgebildet wurde. In einem Ring von 20–30 km um Hagen sind die Wohnstandortentscheidungen allerdings im Vergleich zum näheren Umland (〈 20 km von Hagen) mit deutlich längeren Pendeldistanzen nach dem Umzug verbunden, was den klassischen Befunden der Suburbanisierungsforschung entspricht. Insgesamt sprechen die Ergebnisse für sehr komplexe Beziehungen zwischen Geschlecht, sozialem Status, Wohnstandortwahl und Pendelverhalten. Dies wird auch vor dem Hintergrund der polyzentrischen Struktur der Region interpretiert. Schlussfolgerungen für die weitere Forschung ergeben sich aus einigen innovativen methodischen Ansätzen der Studie. Die planerische Bedeutung der Ergebnisse wird ebenfalls kurz diskutiert.

Beschreibung: Zusammenfassung Der Umgang mit den Folgen des Klimawandels stellt Biosphärenreservate als Modellregionen für nachhaltige Entwicklung vor neue Herausforderungen. Obwohl Einflüsse auf Ökosysteme oder Landschaften nur begrenzt steuerbar und schwer absehbar sind, besteht der Auftrag, Klimawandelfolgen strategisch aufzugreifen. Zudem sind zahlreiche Akteure mit unterschiedlichen Perspektiven in Entscheidungen einzubeziehen, die vor dem Hintergrund unsicherer Zukunftsprognosen getroffen werden müssen. Der Beitrag zeigt am Beispiel des UNESCO-Biosphärenreservates Flusslandschaft Elbe-Brandenburg, welche konkreten Handlungsfelder sich abzeichnen und welche Arbeitsphasen ein planvoller Umgang mit dem Klimawandel haben kann. Es werden mögliche Maßnahmen für die Themen Landschaftswasserhaushalt, Vegetation, Fauna und Landnutzung aufgezeigt. An der Elbe kommt dem Flussgebietsmanagement eine besondere Bedeutung zu. Die Diskussion möglicher strategischer Handlungsfelder erläutert, welche Rollen die Verwaltung von Biosphärenreservaten in einem Prozess der Anpassung an den Klimawandel einnehmen kann. Die Möglichkeiten und der Umfang, in dem sich Biosphärenreservate zu Modellregionen für die Anpassung an den Klimawandel entwickeln, werden sich in der Praxis nach den vorhandenen Kapazitäten und der Expertise richten.

Beschreibung: Decentralized energy systems are increasingly seen as a key factor for a transition towards a low-carbon, renewable energy based society. Within the transition process, regional demand and supply of renewable energy carriers have to be aligned, while considering the environmental conditions of the region. This paper focuses on the energy demand from buildings, which makes up 35% of the total energy demand. It presents an approach for aligning the regional supply potential of renewable energy carriers with the dynamics of regional energy demand from buildings. The approach consists of two components. First, a dynamic model simulates regional energy demand from buildings taking into consideration envelope renovation, legislative standards, and adoption of heating technologies. Second, the regional supply is estimated based on the technical maximum possible, taking into consideration competing uses and spatial limitations. We show a first application in the case of the energy region Weiz-Gleisdorf, Austria, which aims to achieve CO2 neutrality and energy self-sufficiency by the year 2050. Our results show that in the year 2050 (i) energy demand from buildings will decrease by 40–55%, depending on envelope renovation rates and legislative standards; (ii) demand for the different renewable energy carriers will be determined by the choice of heating technology; (iii) the demand for wood could be met from regional forest resources, as long as there are no additional demands for other purposes; (iv) the demand for biomass for district heating would require 5–10% of the agricultural area to be used for the production of energy plants rather than food; and (v) in contrast to other forms of energy, the demand for electricity will remain constant or increase slightly over time. This demand could only be regionally met if significant areas of façades or gardens are used for photovoltaic electricity production in addition to roofs. Overall we identified several issues related to spatial planning and a need for further research regarding the transition towards decentralized energy systems. First, if biomass for central district heating systems is to come from regional production, areas should be allocated for cultivating energy crops used specifically to produce fuel. Second, if wood is used for district heating purposes, the extent to which the import of wood from neighboring regions would be a useful ecological solution must be evaluated; this would involve extending regional energy planning beyond the typical jurisdictional boundaries while considering ecological issues.

Beschreibung: Zusammenfassung Stationärer Einzelhandel und (Innen-) Stadt sind räumlich betrachtet eng miteinander verflochten. Durch die zunehmende Relevanz des Internets und insbesondere des damit verbundenen Online-Handels im Alltag der Menschen verliert der physische Raum als konstantes Bindeglied aktuell jedoch immer mehr an Bedeutung. Vor dem Hintergrund der allgemeinen Zeitknappheit und den Vorzügen, welche der Online-Handel bietet, werden immer mehr Produkte online und nicht im stationären Einzelhandel erworben. Dies schlägt sich auch in der Umsatzentwicklung nieder. Während der stationäre Einzelhandel in den letzten Jahren nahezu stagnierende Umsätze zu verzeichnen hat, sind die Wachstumsraten im Online-Handel immens. Bis 2025 soll der Online-Anteil am gesamten Einzelhandelsumsatz auf rund 15 % anwachsen. Dies bleibt nicht ohne Folgen für innerstädtische Einzelhandelslagen. Es wird – abhängig von ihrer Lokalisierung in räumlich-strukturell begünstigten oder benachteiligten Städten – sowohl Gewinner als auch Verlierer geben. Um die Folgen für die davon betroffenen Räume möglichst gering zu halten, sollten die Möglichkeiten, welche die zunehmende Digitalisierung bietet, als Chance für die Attraktivitätssteigerung der innerstädtischen Einzelhandelslagen genutzt werden.

Beschreibung: Zusammenfassung Zur Analyse des Mobilitätsverhaltens von Personen gibt es eine Vielzahl quantitativer und qualitativer Methoden. GPS-Tracking hat sich in den letzten Jahren zu einem festen Bestandteil bei der Erforschung des (touristischen) Mobilitätsverhaltens entwickelt. Basierend auf den – beispielsweise durch GPS-Datenlogger – erfassten Strecken lässt sich das raum-zeitliche Verhalten von Personen analysieren. Weitergehende Fragestellungen, z. B. zu deren Handlungen im Sinne von Aktivitäten am „Point of Interest“ (PoI), zur Motivation (beispielsweise für das Verweilen an einem bestimmten PoI), zu personenbezogenen Daten oder zur Zufriedenheit können durch eine Kombination mit anderen Erhebungstechniken erfasst werden. Eine eigens an der Hochschule Harz entwickelte Android-Applikation für Tablet-Computer ermöglicht die Verknüpfung sich ergänzender empirischer Techniken: GPS-Tracking und Face-to-Face-Befragung. Die Besonderheit liegt hierbei in der entwickelten Software, dem GimToP-Toolkit (GTK). Mit dessen Hilfe ist es möglich, direkt im Anschluss an die zurückgelegte Strecke die Tracks inklusive Pausen in einer interaktiven Karte darzustellen. Somit können die Probanden direkt nach Zurücklegen ihrer Strecke zu den einzelnen Wegepunkten, an denen sie länger verweilten, befragt werden. Dies stellt einen neuen, aussichtsreichen Ansatz für die Erforschung des raum-zeitlichen Verhaltens von Personen (z. B. Wanderern, Städtetouristen, Besuchern von Freizeiteinrichtungen und Sehenswürdigkeiten) dar. Die wichtigsten Ziele, Elemente und Möglichkeiten der neuen Software werden im vorliegenden Beitrag ebenso dargestellt wie Ergebnisse einer Beispieluntersuchung mittels des GTK von Wanderern am Brocken.

Beschreibung: Zusammenfassung Berufsbedingtes Pendeln ist ein wachsendes Phänomen. Eine immer größere Zahl an Beschäftigten legt dabei immer weitere Wege zwischen Wohn- und Arbeitsort zurück. Die Untersuchung beschäftigt sich mit dem Zusammenhang zwischen Pendeln und der Integration in den Arbeitsmarkt. Auch die Umzugsbereitschaft der Beschäftigten wird vor dem Hintergrund personenbezogener Merkmale untersucht. Dazu werden die Daten von rund 730.000 sozialversicherungspflichtig Beschäftigten, die am 30.06.2000 einen Arbeits- oder Wohnort in Hamburg hatten, über einen Zeitraum von 13 Kalenderjahren betrachtet. Die Ergebnisse sind differenziert: Einpendler sind hinsichtlich der Arbeitsmarktintegration recht erfolgreich, aber Pendler nicht generell erfolgreicher als Nichtpendler, wie am Beispiel der Auspendler deutlich wird. Die Arbeitsmarktintegration hat einen Bezug zu räumlicher Mobilität und deren zeitlicher Dynamik, der Zusammenhang ist aber nicht in jedem Fall eindeutig. Im Hinblick auf die Umzugsbereitschaft der sozialversicherungspflichtig Beschäftigten konnten die Ergebnisse der Mobilitätsforschung im Wesentlichen bestätigt werden.

Beschreibung: Zusammenfassung Das vorgestellte Modellvorhaben der Raumordnung „Vorsorgendes Risikomanagement in der Regionalplanung“ befasste sich mit der exemplarischen Entwicklung, Anwendung und Dokumentation eines integrierten Ansatzes zur Risikovorsorge im Rahmen der Regionalplanung am Beispiel der Planungsregion Köln. Dabei waren die Belange kritischer Infrastrukturen besonders zu würdigen. Die Bearbeitung des Projekts erfolgte im Sinne der Modellprojektforschung des Bundes in enger Kooperation mit den Dezernaten Regionalentwicklung, Wasserwirtschaft und Immissionsschutz der Bezirksregierung Köln. Das Projekt folgte konzeptionell einem integrierten Risiko-Governance Ansatz. Regionalplanerisch relevant sind dabei Risiken aus solchen Gefährdungen, die im Sinne des § 1 Abs. 1 bzw. § 8 Abs. 6 ROG raumbedeutsam sind: Sie erfordern somit eine überörtliche, überfachliche Betrachtung, weil ihre Auswirkungen bzw. Vermeidungs- und/oder Bewältigungsstrategien von überörtlicher Bedeutung sind. Dieser Definition folgend wurden für die Betrachtung in der Region Köln die vier Gefahrenkomplexe Flusshochwasser, Erdbeben, technische Störfälle und Hitze ausgewählt. Für diese vier Gefahrenkomplexe wurden Gefährdungs- und Empfindlichkeitsstufen in Anlehnung an eine vom Bundesamt für Bevölkerungsschutz und Katastrophenhilfe entwickelte Methodik bestimmt und zu einem Risikoindex verschnitten. Die Einteilung in Gefährdungsstufen wurde in Abstimmung mit den fachlich zuständigen Experten und Expertinnen der Bezirksregierung vorgenommen. Dem gleichen Ansatz folgte die Bestimmung der Empfindlichkeit der einzelnen im Regionalplan festlegbaren Raumnutzungen und Raumfunktionen gegenüber jedem Gefahrenkomplex. Auf dieser methodischen Grundlage wurde schließlich eine GIS-basierte Risikoanalyse durchgeführt. Die wichtigsten Ergebnisse daraus sind Gefahren-, Empfindlichkeits- sowie Risikokarten für Flusshochwasser, Erdbeben und technische Störfälle – sowohl für die gesamte Region und (mit einer feineren Auflösung) für ausgewählte Hot Spots. Darauf aufbauend wurden Vorschläge für mögliche Plansätze erarbeitet, die sich als Abwägungsgrundlage verstehen. Diese Grundlagen werden von der Bezirksregierung für die anstehende Fortschreibung des Regionalplans genutzt. Neben den methodischen Bausteinen zur Erarbeitung eines Risikoprofils für Regionen gehört zu den Projektergebnissen zudem ein „Fahrplan“ für ein integriertes Risikomanagement in der Regionalplanung, das die Bezirksregierung Köln bei der Fortschreibung des Regionalplans nutzen wird. Besondere Bedeutung werden diese Erkenntnisse auch für die Umweltprüfung haben, da die Behandlung von Klimawandel und die Anpassung an diesen sowie der Umgang mit Katastrophenrisiken durch die Änderungsrichtlinie 2014/52/EU zur gesetzlichen Pflichtaufgabe werden.

Beschreibung: Spruce budworm (Choristoneura fumiferana Clem.) outbreaks cause extensive mortality and growth reductions throughout boreal forests in eastern North America. As tree vulnerability to defoliation remains partially unexplained by tree and stand attributes, we hypothesized that root grafting might attenuate the negative impact of severe defoliation in tree growth. Two experimental sites in the Abitibi-Témiscamingue region dominated by black spruce (Picea mariana Mill.) were harvested and hydraulically excavated to study tree growth in 36 trees in relation to root grafting and the last spruce budworm outbreak using dendroecological methods. Root grafts reduced the negative effects of defoliation by maintaining stable growth in connected trees during epidemic periods. Among dominant trees, growth releases immediately after the outbreak were uniquely observed in grafted trees. Among suppressed trees, grafted trees tended to grow more than non-grafted trees when defoliation severity was the highest. Carbohydrate transfers through root grafts and enhanced efficiency to acquire resources may explain the better performance of grafted trees under scenarios of limited carbon supply. This study reinforces the growing body of literature that suggests root grafting as a cooperative strategy to withstand severe disturbances and highlights the key role of root grafting in stand dynamics to cope with periodic outbreaks.

Beschreibung: The aim of this paper is to present approaches to optimize stand-level, short-rotation coppice management planning, taking into account uncertainty in stand growth due to climate change. The focus is on addressing growth uncertainty through a range of climate scenarios so that an adaptive capacity may be possible and the vulnerability of the stand to climate change may be reduced. The optimization encompasses finding both the harvest age in each cycle and the number of coppice cycles within a full rotation that maximize net present revenue. The innovation lies in the combination of the process-based model (Glob3PG) with two dynamic programming (DP) approaches. The former is able to project growth of eucalypt stands under climate change scenarios. The innovative approaches are thus influential to define the management policy (e.g., stool thinning, number of coppice cycles, and cycle length) that maximizes net present revenue taking into account uncertainty in forest growth due to climate change. In both approaches, the state of the system is defined by the number of years since plantation, whereas DP stages are defined by the cumulative number of harvests. The first approach proposes the optimal policy under each climate change scenario at each state. The second approach addresses further situations when the climate scenario is unknown at the beginning of the planning horizon. Both help address uncertainty in an adaptive framework, as a set of readily available options is proposed for each scenario. Results of an application to a typical Eucalyptus globulus Labill. stand in central Portugal are discussed.

Beschreibung: In the western United States, forests are experiencing novel environmental conditions related to a changing climate and a suppression of the historical fire regime. Mixed-conifer forests, considered resilient to disturbance due to their heterogeneity in structure and composition, appear to be shifting to a more homogeneous state, but the timescale of these shifts is not well understood. Our objective was to assess the effects of climate and fire suppression on stand dynamics and demographic rates of an old-growth mixed-conifer forest in the Sierra Nevada. We used a Bayesian hierarchical analysis to quantify species and community rates of recruitment, growth, and mortality. Despite a warming climate, we found that stand density, basal area, and carbon have increased over 56 years. Fir recruitment and growth significantly exceeded the community-level median rates, whereas pine recruitment and growth was significantly lower than the community-level median rates. Shifts in species composition from a well-mixed stand to a more dense fir-dominated stand appear to be driven by low growth and recruitment rates of pines relative to firs. In forests such as these with consistent and relatively low mortality rates, we recommend that restoration and management activities be focused on promoting pine recruitment and growth.

Beschreibung: The choice of a baseline against which to evaluate changes in carbon stocks is a critical component of any forest carbon offset market. In this paper, we use a discrete dynamic programming model and data from a lodgepole pine (Pinus contorta Douglas ex Loudon) stand in northeastern British Columbia, Canada, to demonstrate that different baselines have little or no effect on optimal harvest decision but can have a large impact on economic returns to a landowner. The results reveal that the magnitude of the financial return to the landowner is dependent on the starting conditions of both the predetermined baseline and the proposed carbon offset project. The study also shows that when given the choice between alternative baselines, a landowner will always choose a fixed baseline over a business-as-usual baseline.

Beschreibung: In forest firefighting, the longer the fires wait, the larger they grow and the longer they take to control. This study concerns the optimal deployment of single forest suppression processor of initial attack in the case of fires ignited simultaneously. The aim is to minimize the total damage caused by the fires to the burnt areas when all fires are suppressed. In Rachaniotis and Pappis (Can. J. For. Res. 36: 652–658, 2006), they use the concept of start-time dependent job processing times for modelling the time needed for fire suppression. The model is intricate but interesting in the sense that is based on theoretical and empirical research in the field of forest firefighting. As a continuation, a stochastic formulation that includes unpredicted parameters in the proposed model is considered and the “dynamic allocation index” rule is used to solve the problem. The optimality of this rule and its effectiveness are proven. Experimental results depict the framework, and inside it, the forest suppression processor achieves greater efficiency.

Beschreibung: An endophytic diazotroph, Paenibacillus polymyxa P2b-2R, has been shown to colonize internal tissues of lodgepole pine (Pinus contorta var. latifolia Engelm. ex S. Watson) and stimulate seedling growth possibly through nitrogen (N) fixation in an N-limited environment. We evaluated the effects of different soil N concentrations on lodgepole pine seedling growth after inoculation with P2b-2R in a year-long greenhouse study. Seedlings were subjected to monthly application of a nutrient solution containing one of four soil N concentrations as Ca(NO3)2 (5% 15N label): 0.0029, 0.029, 0.29, and 2.9 μmol·L–1, referred to as very low, low, medium, and high soil N treatments, respectively. Foliar 15N atom percent excess and foliar N content values of P2b-2R inoculated seedlings were not significantly different from controls at any N treatment. Similarly, rhizospheric and endophytic population of P2b-2R did not vary significantly across N treatments. Inoculation with P2b-2R resulted in seedling growth inhibition during early stages of the experiment; however, by month 12, inoculated seedlings from the very low soil N treatment had accumulated 56.3% and 46.4% more root and shoot biomass than controls, respectively. These results suggest that pine biomass stimulation by P2b-2R may depend on soil N concentrations and that such growth stimulation may occur without providing significant amounts of fixed N.

Beschreibung: We report long-term patterns of quaking aspen (Populus tremuloides Michx.) recruitment for five ungulate exclosures in the northern ungulate winter range of Yellowstone National Park. Aspen recruitment was low (1 m in height increased over 30-fold (from 105 to 3194 aspen·ha−1). Increased heights of young aspen occurred primarily from 2007 to 2012, a period with relatively high predator–prey ratios, declining elk numbers, and decreasing browsing rates. Consistent with a re-established trophic cascade, aspen stands in Yellowstone’s northern range have increasingly begun to recover.

Beschreibung: Under climate change, the importance of biomass resources is likely to increase and new approaches are needed to analyze future material and energy use of biomass globally and locally. Using Sweden as an example, we present an approach that combines global and national land-use and forest models to analyze impacts of climate change mitigation ambitions on forest management and harvesting in a specific country. National forest impact analyses in Sweden have traditionally focused on supply potential with little reference to international market developments. In this study, we use the global greenhouse gas concentration scenarios from the Intergovernmental Panel for Climate Change to estimate global biomass demand and assess potential implications on harvesting and biodiversity in Sweden. The results show that the short-term demand for wood is close to the full harvesting potential in Sweden in all scenarios. Under high bioenergy demand, harvest levels are projected to stay high over a longer time and particularly impact the harvest levels of pulpwood. The area of old forest in the managed landscape may decrease. This study highlights the importance of global scenarios when discussing national-level analysis and pinpoints trade-offs that policy making in Sweden may need to tackle in the near future.

Beschreibung: After affecting millions of hectares of pine forests in western Canada, the mountain pine beetle (MPB; Dendroctonous ponderosae Hopkins) is spreading out of its native range and into Canada’s boreal forest. Impacts of outbreaks can be environmental, economic, and social, and an ecosystem services (ES) viewpoint provides a useful perspective for an integrated approach to assessing these impacts and may help to identify how possible management strategies could minimize these impacts. In this regards, a comprehensive overview of the ecosystem functions and socioeconomic factors that have been impacted by the current outbreaks in western Canada was carried out to facilitate a more general ES assessment. In addition to timber production, current MPB outbreaks have negative effects on provisioning services (water supply and food production) and aesthetic cultural services, while effects on regulating services (carbon and forest fire) are still in debate. Among the supporting services, nutrient cycling and aquatic habitat showed short- and long-term negative effects, while terrestrial habitat showed a mostly positive response. The overall impact on ES may be more severe if salvage logging is practiced as a post-MPB forest management strategy. The outcomes of this study may help to identify areas of greatest socioecological vulnerability to MPB and identify knowledge gaps and avenues for research to advance the ES framework for MPB outbreak management.

Beschreibung: We applied a classic logistic regression (LR) model together with a geographically weighted logistic regression (GWLR) model to determine the relationship between anthropogenic fire occurrence and potential driving factors in the Chinese boreal forest and to test whether the explanatory power of the LR model could be increased by considering geospatial information of geographical and human factors using a GWLR model. Three tests, “all variables”, “significant variables”, and “cross-validation”, were applied to compare model performance between the LR and GWLR models. Our results confirmed the importance of distance to railway, elevation, length of fire line, and vegetation cover on fire occurrence in the Chinese boreal forest. In addition, the GWLR model performs better than the LR model in terms of model prediction accuracy, model residual reduction, and spatial parameter estimation by considering geospatial information of explanatory variables. This indicates that the global LR model is incapable of identifying underlying causal factors for wildfire modeling sufficiently. The GWLR model helped identify spatial variation between driving factors and fire occurrence, which can contribute better understanding of forest fire occurrence over large geographic areas and the forest fire management practices may be improved based on it.

Beschreibung: Soil organic carbon (C), accumulated over millennia, comprise more than half of the C stored in boreal and temperate forest landscapes. We used the Norwegian national forest inventory and soil survey network (n = 719, no deep organic soils) to explore the validity of a deterministic model representation of this pool (Yasso07). We statistically compared simulated and measured soil C stocks and related differences (measured – simulated) to site factors (drainage, topography, climate, vegetation, C-to-N ratio, and soil classification). Median C stocks were 5.0 kg C·m−2 (model) and 14.5 kg C·m−2 (measurements). Soil C differences related to site factors (r2 of 0.16 to 0.37). For Brunisols, Gleysols, and wet Organic soils, differences related primarily to topographic wetness. For Regosols, Podzols, and Dystric Eluviated Brunisols, they related to climate, profile depth, and, in some cases, drainage class and site index. We argue that soil moisture regimes in our study area overrule tree productivity effects in the determination of soil C stocks and present conditions for soil formation that the model cannot (and does not explicitly) account for. These are processes such as humification and podsolization that involve eluviation and illuviation of dissolved organic C (DOC) with sesquioxides to form spodic B horizons and carbon enrichment due to hampered decomposition in frequently anoxic conditions.

Beschreibung: Changes in the soil carbon stock of Finnish upland soils were quantified using forest inventory data, forest statistics, biomass models, litter turnover rates, and the Yasso07 soil model. Uncertainty in the estimated stock changes was assessed by combining model and sampling errors associated with the various data sources into variance–covariance matrices that allowed computationally efficient error propagation in the context of Yasso07 simulations. In sensitivity analysis, we found that the uncertainty increased drastically as a result of adding random year-to-year variation to the litter input. Such variation is smoothed out when using periodic inventory data with constant biomass models and turnover rates. Model errors (biomass, litter, understorey vegetation) and the systematic error of total drain had a marginal effect on the uncertainty regarding soil carbon stock change. Most of the uncertainty appears to be related to uncaptured annual variation in litter amounts. This is due to fact that variation in the slopes of litter input trends dictates the uncertainty of soil carbon stock change. If we assume that there is annual variation only in foliage and fine root litter rates and that this variation is less than 10% from year to year, then we can claim that Finnish upland forest soils have accumulated carbon during the first Kyoto period (2008–2012).

Beschreibung: This work presents applications of the linear mixed-effects model calibration to predict individual tree volumes of Eucalyptus grandis W. Hill ex Maiden plantations on first and second rotations located in different farms of the same region in São Paulo, Brazil. We started with the Schumacher and Hall equation in its linearized form to develop our mixed-effects model. Some parameters were considered as random among the different farms, and the calibration was made at the farm level using a small number of sample trees. The approach was developed for univariate models of the first rotation, which were calibrated with first- and second-rotation trees, and for bivariate models of the two rotations, which were calibrated with first-rotation trees. The results showed that the calibrated mixed model provides more reliable predictions than the fixed part of the model alone; however, the benefit is only moderate due to the rather small variation of the stem form between farms and rotations. The results indicate that the approach can reduce the measurement requirements on second-rotation crops.

Beschreibung: This study aimed to characterize the vertical distribution of longhorned beetle larvae in burned trees of the eastern Canadian boreal forest. Black spruce (Picea mariana (Mill.) Britton, Sterns & Poggenb.) and jack pine (Pinus banksiana Lamb.) trees burned at three severity levels were cut, and 30 cm boles were collected from the ground up to a height of 9.45 m. Boles were debarked and dissected to collect insect larvae. Results show that the three most abundant longhorned beetle species were vertically segregated among burned jack pine and black spruce trees, but the section having the highest timber value was heavily infested by woodborer larvae. Larval density distribution of Monochamus scutellatus scutellatus (Say) and of Acmaeops proteus proteus (Kirby) could be linked with bark thickness, which also depends on fire severity. Lightly burned stands of black spruce were the most heavily infested and should be salvaged only if they are easily accessible and can thus be rapidly harvested and processed at the mill. More severely burned stands should be salvaged later as they will be less affected by woodborers, as should jack pine, which is lightly infested compared with black spruce. The ecological role of stumps should be further investigated because they could still have an ecological value after salvage logging as Arhopalus foveicollis (Haldeman) uses them specifically.