ALBERT

Description: 〈p〉Publication date: 1 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Forest Ecology and Management, Volume 449〈/p〉 〈p〉Author(s): Yili Guo, Han Y.H. Chen, Azim U. Mallik, Bin Wang, Dongxing Li, Wusheng Xiang, Xiankun Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Litterfall production is a major contributor to ecosystem net primary productivity and biogeochemical cycles. However, how various abiotic and biotic drivers influence litterfall production in heterogeneous natural forests is still debated. We used structural equation models (SEM) to test the direct and indirect effects of tree species diversity, tree diameter variation, stand basal area, and abiotic drivers (canopy exposure, elevation, slope, convexity, aspect, topographic wetness index and altitude above channel) on annual litterfall production in a heterogeneous tropical karst seasonal rainforest in Southern China. The SEM with tree species diversity, tree diameter variation, stand basal area, and abiotic drivers accounted for 43.4% of the variation in annual litterfall production. Tree species diversity and stand basal area had positive direct effects, while tree diameter variation had a negative direct effect on annual litterfall production. Tree species diversity had no significant effect on tree diameter variation nor stand basal area. Both annual litterfall production and tree species diversity decreased directly with water availability, while canopy exposure positively affected annual litterfall production but not tree species diversity. Our results indicate that the positive relationship between tree species diversity and litterfall production did not result from the effects of species diversity on canopy packing; instead, it appears that increasing soil water availability simultaneously reduce tree species diversity and annual litterfall production in the tropical karst seasonal rainforest.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Forest Ecology and Management, Volume 449〈/p〉 〈p〉Author(s): Paulo Cañete-Salinas, Francisco Zamudio, Marco Yáñez, Javier Gyenge, Héctor Valdés, Cristian Espinosa, Francisco Jara-Rojas, Jaime Venegas, Luis Retamal, César Acevedo-Opazo〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Water is the main limiting factor for poplar plantations in the Mediterranean zone of central Chile. Overall, water requirements in these plantations may be estimated using climatic and soil moisture data. However, irrigation strategies can be improved if growth and plant water status are considered. The aim of this study was to assess the growth (diameter increments) and leaf-level physiology (xylem water potential (Ψ〈sub〉x〈/sub〉) and stomatal conductance (g〈sub〉s〈/sub〉)) responses of two 〈em〉Populus × canadensis〈/em〉 clones (‘I-214’ and ‘I-488’) to different irrigation frequencies. The study was carried out during three growing seasons in commercial plantations located in the Maule Region, central Chile. Three irrigation frequencies were evaluated: an over-irrigation frequency (21 days) (T1); a standard irrigation frequency used operationally in the area (28 days) (T2) and a deficit irrigation frequency (35 days) (T3), while the watering time was held constant for all treatments. Although both clones belong to the same interspecific cross, they differed in their growth and physiological responses to water deficit. Compared with ‘I-214’, ‘I-488’ was more sensitive to lower irrigation frequencies (higher water restriction), which decreased the diameter increments, the water potential and stomatal conductance. The results suggest that the use of physiological and climatic information may improve water management on commercial poplar plantations.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Forest Ecology and Management, Volume 448〈/p〉 〈p〉Author(s): Miaomiao Zhao, Jilin Yang, Na Zhao, Yu Liu, Yifu Wang, John P. Wilson, Tianxiang Yue〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Forests are a major contributor of terrestrial ecosystem carbon pools. Accurate estimates of forest biomass carbon sinks can improve our understanding of carbon cycles and help in developing sustainable forest management policies in the face of climate change. In this study, we update estimates of the biomass carbon stocks of China’s forests based on seven forest inventory datasets from 1977 to 2013 and carbon fraction coefficients of 46 tree species in the continuous biomass expansion factor (CBEF) model. Our findings suggest that: (1) China’s forest stands acted as an average biomass carbon sink of 99.07 Tg C year〈sup〉−1〈/sup〉; and (2) biomass carbon stocks increased by 72.62% from 1977 to 2013 and recently reached 7.27 Pg C, driven by forest area expansion and forest growth. The biomass carbon density of forest stands (canopy coverage 〉20%) increased from 38.18 to 44.52 Mg C ha〈sup〉−1〈/sup〉 during the study period, with higher carbon densities in natural compared to planted forests, and the gap increasing with forest age. The largest increases in the biomass of carbon stocks of forest stands occurred in the eastern and northern regions. Our results suggest that biomass carbon stocks of natural forests account for about 85% in the most recent inventory and that the total biomass carbon stocks of forest stands in China will keep increasing in the future because of the large area of planted forests with young and middle-aged forest growth. The results from this study can help with comprehensive investigations of forest carbon budgets and the calibration and validation of simulation model results.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Forest Ecology and Management, Volume 448〈/p〉 〈p〉Author(s): Steffen Herrmann, Markus O. Huber, Zoe Bont, Andreas Rigling, Jan Wunder〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Wood decay limits the function of Norway spruce (〈em〉Picea abies〈/em〉 (L.) H.Karst.) for wood production and in protection forests (i.e. forests protecting against natural hazards). Therefore, more detailed knowledge about the presence and extent of decay in living trees is highly relevant for both the timber industry and risk management strategies. However, decay detection in living Norway spruce trees is not sufficiently possible by visual methods. One possibility to overcome this problem are indirect, non- or least-destructive measurement devices such as the decay detector Rotfinder. Yet, the influence of climatic variables on the reliability of decay detection determined with the Rotfinder is not sufficiently known. Therefore, we assessed the influences of several climatic variables on the Rotfinder values continuously over one year at the same measuring position. Additionally, we determined a threshold value for decay detection in single Norway spruce trees in Central Europe. Regardless of the temperature, Rotfinder values measured over one year were mainly influenced by internal decay status, i.e. damage degree, which explained about 85% of the variation based on a generalized linear mixed effects model in this temperature range (about 6–27 °C). Together with fluctuations in air temperature, about 87% of the variation in Rotfinder values could be accounted for. For decay detection in single Norway spruce trees, a maximum threshold value of about 11,000 Rotfinder units (RU) was identified, equivalent to about 36% of the Rotfinder values measured for intact trees. Our results indicate that the Rotfinder can be used successfully for decay detection in single Norway spruce trees under Central European conditions.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Forest Ecology and Management, Volume 448〈/p〉 〈p〉Author(s): Raul Rosenvald, Piret Lõhmus, Riinu Rannap, Liina Remm, Katrin Rosenvald, Kadri Runnel, Asko Lõhmus〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Retention forestry is a silvicultural approach that can achieve both ecological and economic objectives in various forest ecosystems. It builds largely on the assumption that the live trees left unharvested (the main timber cost) effectively support ecological functioning of post-harvest forest. Such effectiveness can be understood as a combination of the initial ecological value of the tree (that may persist after tree death) and its survival, i.e., the prospect to develop into a high-quality veteran tree in the next forest generation. We assessed those aspects among 〉3000 live trees actually retained in 103 Estonian harvested sites and monitored over 16 years. We analysed how their survival and habitat value (estimated from tree morphology, confirmed by epiphyte surveys) translate to the veteran-tree perspectives. Only 48% of the trees were still alive after 16 years, and this final survival at the stand-scale was poorly predictable from a few years of monitoring. Only 12% retention trees had both high habitat value and high survival. Most trees (75%) were of low initial habitat value and, combined with low survival, almost 40% of all trees never provided quality habitat for tree-dwelling species. Nevertheless, we found considerable potential for post-harvest development of habitat value; notably in European nemoral hardwood species (such as 〈em〉Fraxinus, Quercus, Ulmus, Acer〈/em〉), which survived well but were usually in subcanopies at the time of the harvest. These findings indicate that retention forestry can improve also highly impoverished (e.g. short-rotation) forests, if analytical tools have been developed and applied to predict tree survival and future habitat quality.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Forest Ecology and Management, Volume 448〈/p〉 〈p〉Author(s): Quanzhi Zhang, Chuankuan Wang, Zhenghu Zhou〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Quantifying net primary production (NPP) and its allocation is essential for understanding and modeling the carbon (C) cycling in forest ecosystems. We used biometry-based measurements to examine the NPP allocation for six temperate forest types with similar stand age and climate but diverse stand characteristics and site conditions in northeastern China. The forest types included four naturally-regenerated stands and two planted stands. Our objectives were to (1) compare the NPP and its allocation among the six forest types, and (2) explore the factors driving the inter-stand variability of the NPP allocation patterns. We found that the total NPP (TNPP) and NPP of short-lived biomass tissues (NPP〈sub〉SL〈/sub〉) differed significantly among the forest types, varying from 709 to 927 gC m〈sup〉−2〈/sup〉 yr〈sup〉−1〈/sup〉 and from 364 to 594 gC m〈sup〉−2〈/sup〉 yr〈sup〉−1〈/sup〉, respectively. However, the NPP of long-lived tissues (NPP〈sub〉LL〈/sub〉) did not differ significantly among the forest types, varying from 305 to 364 gC m〈sup〉−2〈/sup〉 yr〈sup〉−1〈/sup〉. These results suggested that the production of structural tissues be relatively stable under the same climate, and the inter-stand difference in TNPP be mainly attributed to the difference in NPP〈sub〉SL〈/sub〉. Within the four natural stands, the foliage production was significantly and positively correlated with soil nitrogen (N) (〈em〉R〈/em〉〈sup〉2〈/sup〉 = 0.50) and phosphorus (P) stock (〈em〉R〈/em〉〈sup〉2〈/sup〉 = 0.37), whereas the fine root production was significantly and negatively correlated with soil C:P (〈em〉R〈/em〉〈sup〉2〈/sup〉 = 0.54) and N:P ratio (〈em〉R〈/em〉〈sup〉2〈/sup〉 = 0.47), implying that foliage and root production may be driven by different mechanisms. The convergence of NPP〈sub〉LL〈/sub〉 across forest types with different stand characteristics, site conditions and management practices but under the same climate has important implication in managing forest ecosystems for C sequestration, while the divergence of NPP〈sub〉SL〈/sub〉 implies that vegetation can adapt to the site conditions by changing resource-absorbing tissues production and its allocation.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Forest Ecology and Management, Volume 452〈/p〉 〈p〉Author(s): Alicia Calle, Karen D. Holl〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉To meet their large-scale forest and landscape restoration targets, countries must find ways to accommodate areas for conservation alongside agricultural production. In some pasture-dominated regions of Latin America, intensive silvopastoral systems (SPS) are being promoted to increase cattle productivity on certain lands while facilitating the removal of cattle from marginal areas for forest restoration. However, the recovery of these forests and their contribution to the overall conservation value of the landscape has not been assessed rigorously. We evaluated forest structure and composition in 20 sites in a region of the Colombian Andes where a decade ago farmers transitioned to SPS and fenced off riparian areas to enable forest recovery. We compared these restored forests to a reference model based on the remaining riparian forest across the region, all of which has been subjected to human management. We found that woody species richness was higher in restored than in reference forests, and the proportion of large-seeded, later successional, animal-dispersed species were similar in both forest types. Whereas we found a similar suite of dominant tree species in restored and reference forest, 〈em〉Guadua angustifolia〈/em〉, a native giant bamboo was more abundant in the reference forests due to human management. Total tree basal area was higher in restored forests due to a small number of very large trees likely present in the pastures at the time of site protection. These findings highlight (1) the potential for recovery of diverse forests in riparian sites despite previous grazing use and (2) the role of remnant trees in facilitating natural succession. Overall, rapid forest recovery with minimal intervention in previously farmed lands is good news for conservation in a region that still harbors significant biodiversity despite high levels of fragmentation and the influence of human management.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Forest Ecology and Management, Volume 448〈/p〉 〈p〉Author(s): Joseph Langridge, Benoît Pisanu, Sébastien Laguet, Frédéric Archaux, Laurent Tillon〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Forests constitute one of the most important feeding and foraging habitats for bats. Because bat populations are declining, most likely due to habitat loss or fragmentation, it is imperative to understand the issues concerned with timber exploitation on bat conservation. We investigated the foraging activity of edge- and open-space foragers in relation to stand and vegetation structure, characteristics that are commonly affected by forestry. Acoustic surveys, culminating to 713 point count sites were undertaken covering 46 different forest massifs across mainland France over 6 years. We used generalized linear mixed models to analyse the activity of ten species: 6 edge-habitat and 4 open-habitat foragers. 〈em〉Pipistrellus pipistrellus〈/em〉 was the most detected edge-habitat forager, while 〈em〉Nyctalus leisleri〈/em〉 was the most recorded of the open-habitat foragers. 〈em〉Eptesicus serotinus〈/em〉 and 〈em〉P. pipistrellus〈/em〉 responded positively to heterogeneous vertical vegetation volume. In addition, 〈em〉P. kuhlii〈/em〉 and 〈em〉P. nathusii〈/em〉 responded negatively to tree basal area. 〈em〉Barbastella barbastellus〈/em〉, 〈em〉Hypsugo savii〈/em〉, and 〈em〉P. nathusii〈/em〉 were associated with either ground deadwood and/or logging tracks and minor-traffic roads, confirming the importance of edge space. Finally, 〈em〉B. barbastellus, E. serotinus,〈/em〉 and 〈em〉P. nathusii〈/em〉 were positively linked to the presence of tree microhabitats. This study demonstrates that bat use in forests is complex and multifaceted. Maintaining ground deadwood and heterogeneity of vegetation, at the forest plot scale, should ensure the ecological functioning of exploited forest systems and the conservation of edge- and open-habitat foraging bats.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Forest Ecology and Management, Volume 451〈/p〉 〈p〉Author(s): Thomas P. Sullivan, Druscilla S. Sullivan〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉Restoration practices are much needed on clearcut openings in commercial forest landscapes where some mammal species have declined in abundance from a loss of preferred food, cover, and other components of stand structure. Retention of excess woody debris in piles and windrows provides habitat for forest-floor small mammals and some of their predators such as small mustelids. However, it is unknown if these retention habitats are used over longer periods (〉10 years) as new forests grow and develop on harvested sites, or do they become unoccupied? We tested the hypotheses (H) that (H〈sub〉1〈/sub〉) abundance, species richness, and diversity of the forest-floor small mammal community, and (H〈sub〉2〈/sub〉) reproduction and survival of the southern red-backed vole (〈em〉Myodes gapperi〈/em〉), long-tailed vole (〈em〉Microtus longicaudus〈/em〉), and deer mouse (〈em〉Peromyscus maniculatus〈/em〉) would decline on sites with woody debris structures, compared with sites of dispersed woody debris or uncut forest, up to 12 years post-construction in south-central British Columbia, Canada.〈/p〉 〈p〉Woody debris structures provided habitat on new clearcuts for 〈em〉M. gapperi〈/em〉 at comparable or higher abundance than in uncut forest and 5.0 to 7.6 times higher than on dispersed sites in the first 5-year period. Although numbers declined after the initial three years, populations of 〈em〉M. gapperi〈/em〉 in debris structures recovered to earlier abundance levels at 11–12 years post-construction. Mean abundance of 〈em〉M. longicaudus〈/em〉 was consistently higher (2.8 to 3.5 times) in piles and windrows than in sites with dispersed woody debris over the first 5-year period. Populations of 〈em〉M. longicaudus〈/em〉 were high in all three treatment sites at 11 years post-construction reaching mean annual peak numbers of 24, 42, and 36 voles per ha in the dispersed, piles, and windrow sites, respectively. Mean abundance of 〈em〉P. maniculatus〈/em〉 was similar among treatment sites and consistent over time. Mean abundance of total small mammals was consistently higher (1.8 to 2.4 times) in piles and windrows than dispersed or forest sites in the first 5-year period and this pattern was continued at 11–12 years post-construction. At 11 years post-construction, all treatment sites had the highest peak numbers per ha in the study: dispersed (40.3), piles (64.1), windrows (56.1), and forest (29.0). Our results did not support H〈sub〉1〈/sub〉 as abundance, species richness, and diversity were increased or maintained in the debris structures over the 12-year period. Reproduction and survival followed the pattern of abundance for the major species, and hence H〈sub〉2〈/sub〉 was not supported. Our study is the first to measure long-term (up to 12 years) responses of forest-floor small mammals to constructed piles and windrows of woody debris as a means of habitat retention on clearcuts. These mammalian species, particularly voles, may then serve as prey for marten and other mustelids. This relationship provides further support for piles and windrows to act as baseline trophic structures in ecological restoration of cutover forest land.〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Forest Ecology and Management, Volume 451〈/p〉 〈p〉Author(s): Halina Smal, Sławomir Ligęza, Jacek Pranagal, Danuta Urban, Dorota Pietruczyk-Popławska〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The objective of this study was to investigate the effect of afforestation of post-arable sandy soils (Dystric Arenosols) with Scots pine (〈em〉Pinus sylvestris〈/em〉 L.) on the amount and distribution of C〈sub〉org〈/sub〉, N〈sub〉tot〈/sub〉 and P〈sub〉tot〈/sub〉 stocks between genetic soil horizons. The study was performed at three locations with five classes of afforestation each: 10-, 20-, 30-, 40-, 50-year-old stands, which additionally included the arable and the continuous forest soils as reference. The soil was sampled by genetic horizon, including the organic one, down to 100 cm, from its whole thickness, and from A horizon of the afforested soils from: 0–5, 5–10 and 10–20 cm. In the organic horizon of the afforested soils, the stock of C〈sub〉org〈/sub〉, N〈sub〉tot〈/sub〉 and P〈sub〉tot〈/sub〉 increased significantly with stand age, and an average rate of accumulation was 33.6, 1.30 and 0.04 g m〈sup〉−2〈/sup〉 year〈sup〉−1〈/sup〉 respectively. C〈sub〉org〈/sub〉 stocks in the former plough layer were found to decrease within the first decade of afforestation, and subsequently, the values gradually increased. With organic horizon included the respective stocks reached the level comparable with the related horizon of the arable soil after approx. 20–30 years. Subsoil B, BC and C horizons together accounted for approx. 35% of the C〈sub〉org〈/sub〉 stocks in the entire profile. N〈sub〉tot〈/sub〉 stocks in mineral soil horizons initially dropped in the first decade after afforestation, which was subsequently followed by an increase; however, after 50 years, still the observed values were lower in comparison with both the respective arable and continuous forest soils. P〈sub〉tot〈/sub〉 stocks in the mineral soil horizon declined over the chronosequence, and in the profile at 50-year-old stands, they were lower in comparison with both the arable and the continuous forest soils. Stand age and sampling by genetic horizons, including the organic horizon, from the entire soil profile should be considered for estimation of changes in C〈sub〉org〈/sub〉, N〈sub〉tot〈/sub〉 and P〈sub〉tot〈/sub〉 stocks following afforestation of agricultural soils.〈/p〉〈/div〉 〈/div〉