Carbon Accumulation Patterns During Post-Fire Succession in Cajander Larch (Larix cajanderi) Forests of Siberia

Increased fire activity within boreal forests could affect global terrestrial carbon (C) stocks by decreasing stand age or altering tree recruitment, leading to patterns of forest regrowth that differ from those of pre-fire stands. To improve our understanding of post-fire C accumulation patterns within boreal forests, we evaluated above- and belowground C pools within 17 Cajander larch (Larix cajanderi) stands of northeastern Siberia that varied in both years since fire and stand density. Early-successional stands (<20-year old) exhibited low larch recruitment, and consequently, low density, aboveground larch biomass, and aboveground net primary productivity (ANPP_tree). Mid-successional stands (21- to 70-year old) were even-aged with considerable variability in stand density. High-density mid-successional stands had 21 times faster rates of ANPP_tree than low-density stands (252 vs. 12?g?C?m^?2?y^?1) and 26 times more C in aboveground larch biomass (2,186 vs. 85?g?C?m^?2). Density had little effect on total soil C pools. During late-succession (>70-year old), aboveground larch biomass, ANPP_tree, and soil organic layer C pools increased with stand age. These stands were low density and multi-aged, containing both mature trees and new recruits. The rapid accumulation of aboveground larch biomass in high-density, mid-successional stands allowed them to obtain C stocks similar to those in much older low-density stands (~8,000?g?C?m^?2). If fire frequency increases without altering stand density, landscape-level C storage could decline, but if larch density also increases, large aboveground C pools within high-density stands could compensate for a shorter successional cycle.     

黑龙江省大兴安岭林区火烧迹地森林更新及其影响因子

林火干扰是大兴安岭森林更新的影响因子之一,研究火烧迹地森林更新的影响因子(立地条件、火前植被、火干扰特征)对理解生态系统的结构、功能和火后演替轨迹具有重要意义。选取呼中及新林林业局55个代表性火烧样地,利用增强回归树分析法分析了火烧迹地森林更新的影响因素。结果表明:(1)立地条件是影响针、阔叶树更新苗密度的主要因素;海拔对针叶树更新苗密度的影响最大;坡度对阔叶树更新苗密度影响最大;(2)距上次火烧时间对针叶树更新苗比重影响最大,其次是林型;(3)中度林火干扰后森林更新状况好于轻度和重度火烧迹地。根据火烧迹地森林更新调查分析可知:林型影响火后演替模式,火前为针叶树或阔叶树纯林,火后易发生自我更新(火后树种更新组成与火前林型相同),而针阔混交林在火干扰影响下易于发生序列演替(火后初期以早期演替树种更新为主)。     

Estimation of forest-stand net primary productivity using fraction phytomass distribution model

Methods for assessing the primary productivity of the forest stands between various tree species in different environmental conditions are considered. Methods for the primary productivity assessment using data on the phytomass fractions and stand wood stock have been proposed. It is shown that the Zipf-Pareto equation of the relationship between the phytomass of some tree fractions in the stand can be used for a primary productivity estimation of the stock volume. A model analogous to R. Solow’s macroeconomic model has been proposed to describe the processes of the phytomass growth in the forest stand.     

Impacts of fire severity and post-fire reforestation on carbon pools in boreal larch forests in Northeast China

Aims Boreal larch (Larix gmelinii) forests in Northeast China have been widely disturbed since the 1987 conflagration; however, its long-term effects on the forest carbon (C) cycling have not been explored. The objective of this study thus was to quantify the effects of fire severity and post-fire reforestation on C pools and the changes of these forests.Methods Sixteen permanent plots have been set in two types of larch stands (L. gmelinii -grass, LG; and L. gmelinii-Rhododendron dahurica, LR) with three levels of fire severity (unburned, low-severity and high-severity but replanted), at 1987 burned sites in Daxing'anling, northeastern China, to repeatedly measure ecosystem C pools in 1998 and 2014. C components were partitioned into vegetation (foliage, branch, stem and roots), soil and detritus (standing and fallen woody debris and litter). The fire effects on post-fire C dynamics were examined by comparing the differences of C pools and changes between the two field investigations caused by fire severity.Important findings During the study period, unburned mature stands were C sinks (105g C m ?2 year^-1 for LG, and 190g C m ?2 year^-1 for LR), whereas the low-severity stands were C-neutral (?4 and 15g C m ?2 year^-1 for LG and LR, respectively). The high-severity burned but reforested stands were C sinks, among which, however, magnitudes (88 and 16g C m ?2 year^-1 for LG and LR, respectively) were smaller than those of the two unburned stands. Detritus C pools decreased significantly (with a loss ranging from 26 to 38g C m ?2 year^-1) in the burned stands during recent restoration. Soil organic C pools increased slightly in the unmanaged stands (unburned and low-severity, with accumulation rates ranging from 4 to 35g C m ?2 year^-1), but decreased for the high-severity replanted stands (loss rates of 28 and 36g C m ?2 year^-1 for LG and LR, respectively). These results indicate that fire severity has a dynamic post-fire effect on both C pools and distributions of the boreal larch forests, and that effective reforestation practice accelerates forest C sequestration.     

The influence of fire on carbon distribution and net primary production of boreal Larix gmelinii forests in north-eastern China

The boreal larch forest of Eurasia is a widespread forest ecosystem and plays an important role in the carbon budget of boreal forests. However, few carbon budgets exist for these forests, and the effects of wildfire, the dominant natural disturbance in this region, on carbon budgets are poorly understood. The objective of this study was to quantify the effects of wildfire on carbon distribution and net primary production (NPP) for three major Dahurian larch (Larix gmelinii Rupr.) forest ecosystems in Tahe, Daxing'anling, north‐eastern China: Larix gmelinii–Ledum palustre, Larix gmelinii–grass and Larix gmelinii–Rhododendron dahurica forests. The experimental design included mature forests (unburned), and lightly and heavily burned forests from the 1.3‐million‐ha 1987 wildfire. We measured carbon distribution and above‐ground NPP, and estimated fine root production from literature values. Total ecosystem carbon content for the mature forests was greatest for Larix–Ledum forests (251.4 t C ha^?1) and smallest for Larix–grass forests (123.8 t C ha^?1). Larix–Ledum forests contained the smallest vegetation carbon (13.5%), while Larix–Rhododendron contained the largest vegetation carbon (63.1%). Fires tended to transfer carbon from vegetation to detritus and soil. Total NPP did not differ significantly between the lightly burned and unburned stands, and averaged 1.58, 1.29 and 1.01 t C ha^?1 year^?1 for Larix–grass, Larix–Rhododendron and Larix–Ledum lightly burned stands, respectively. Above‐ground net primary production (ANPP) of heavily burned stands was 92–95% less than unburned and lightly burned stands. The estimated carbon loss during the 1987 fire showed substantial variability among forest types and fire severity levels. Depending upon the assumptions made about the fraction of the landscape occupied by the three larch forest types, the 1987 conflagration in north‐east China released 2.5 × 10⁷?4.9 × 10⁷ t C to the atmosphere. This study illustrates the need to distinguish between the different larch forests for developing general carbon budgets.     

Buried charcoal layer and ectomycorrhizae cooperatively promote the growth of Larix gmelinii seedlings

Charcoal produced by fire on the soil surface mixes into the soil over time and is heterogeneously distributed within the soil profile in post-fire forests. To determine how different patterns of vertical distribution of charcoal and ectomycorrhizal formation affect the growth of Larix gmelinii (Gmelin larch) in post-fire forests, we conducted a model experiment in the pots. In this study, pots with a layer of charcoal in the middle of the soil profile promoted growth of the root system of the seedlings significantly more than did pots with no charcoal or with charcoal scattered throughout the soil. Along with the development of the root system, above-ground biomass and total biomass were also increased. Furthermore, in addition to the positive effects of charcoal in the soil, there were also strong positive effects on the growth of seedlings from ectomycorrhizal root formation. As a result, the largest above-ground biomass and total biomass were found for seedlings grown in layered charcoal with ectomycorrhizae. Furthermore, the highest phosphorus concentration in needles was also found for seedlings grown in layered charcoal with ectomycorrhizae. This is attributable to the frequent contact of roots with charcoal in the middle layer of the soil and the utilisation of phosphate by ectomycorrhizae. This suggests that buried and layered charcoal occurring in patches in post-fire stands may provide a suitable habitat for the growth of Gmelin larch seedlings.     

Post-logging organic matter recovery in forest ecosystems of eastern Baikal region

The dynamics of organic matter accumulated in the soil and main vegetation elements was analyzed for post-logging forest ecosystem succession series in eastern Baikal region. The phytomass was found to allocate up 63 and 50% of carbon in undisturbed Scots pine and fir stands, respectively. The post-logging phytomass contribution to the total carbon pool appeared to decrease down to 16% in Scots pine and 6% in fir stands. In Scots pine stands, carbon storage was determined to account for almost 70% of the initial carbon 60 years after logging. In 50- to 55-year-old fir stands, carbon recovered its initial pool only by 10%. Soil carbon recorded in recently logged Scots pine and fir sites appeared to be 5 and 16 times that accumulated in the phytomass, respectively. The ratio between phytomass carbon and soil organic matter recovered back to the prelogging level in Scots pine stands by the age of 50–60 years. While phytomass carbon also increased in fir stand of the same age, it did not reach the level of the control stand.     

Remote sensing approach to detect post-fire vegetation regrowth in Siberian boreal larch forest

Remote sensing with time series data offers considerable potential in the trajectory of post forest fire dynamics beyond the current monitoring of structural attributes that are displayed in the post-fire area. Many studies have addressed this topic by using time series remote sensing indices; however, this approach has sometimes been demonstrated as an unrealistic and biased representation of the post-fire forest patterns due to the saturation issues of vegetation indices. These saturation issues then lead to an underestimation of the forest successional stages and an overestimation of the forest recovery rate. This paper aims to develop a framework for trajectory of the post-fire forest patterns in the Siberian boreal larch forest (Larix sibirica) with the synergistic use of different remote sensing based vegetation-cover indicators derived from the Landsat time series and the WorldView-2 images. A time-series of the forest recovery index (FRI) and fractional vegetation cover (FVC) has been analyzed to estimate the rates of forest regeneration and vegetation recovery across different burn severity levels in the Siberian larch forest. The results showed that the FRI method can be used to observe the regrowth of the larch forest from the tenth year after the fire overlapping with the period of significant increase in the sapling stem volume. The post-fire larch forest canopy can fully recover to the pre-fire condition with respect to the magnitude of the FRI values after 30–47 years where the highest regeneration rate was observed in the moderate burn severity areas followed by the low and high burn severity. On the other hand, the FVC method was positively correlated with burn severity and more sensitive for evaluating the early stages of the forest succession in which the FVC dramatically increases after 5–6 years after the fire. The significant growth of FVC was accentuated by the maximum emergence of the sapling density as well as the rapid growth of herbaceous plants, grasses, shrubs, and shade-intolerant trees immediately after the fire, which could not be evaluated using the FRI. Both time series of the FRI and the FVC are valuable tools for determining the dominant stages of the post-fire larch forest succession in order to understand the relationships between fire disturbance and natural cycles of the boreal larch forest.     

Growth decline linked to warming-induced water limitation in hemi-boreal forests

Hemi-boreal forests, which make up the transition from temperate deciduous forests to boreal forests in southern Siberia, have experienced significant warming without any accompanying increase in precipitation during the last 80 years. This climatic change could have a profound impact on tree growth and on the stability of forest ecosystems in this region, but at present evidence for these impacts is lacking. In this study, we report a recent dramatic decline in the growth of hemi-boreal forests, based on ring width measurements from three dominant tree-species (Pinus sylvestris, Larix sibirica and Larix gmelinii), sampled from eight sites in the region. We found that regional tree growth has become increasingly limited by low soil water content in the pre- and early-growing season (from October of the previous year to July of the current year) over the past 80 years. A warming-induced reduction in soil water content has also increased the climate sensitivity of these three tree species. Beginning in the mid-1980s, a clear decline in growth is evident for both the pine forests and the larch forests, although there are increasing trends in the proxy of soil water use efficiencies. Our findings are consistent with those from other parts of the world and provide valuable insights into the regional carbon cycle and vegetation dynamics, and should be useful for devising adaptive forest management strategies.     

Rapid Increases in Forest Understory Diversity and Productivity following a Mountain Pine Beetle (Dendroctonus ponderosae) Outbreak in Pine Forests

The current unprecedented outbreak of mountain pine beetle (Dendroctonus ponderosae) in lodgepole pine (Pinus contorta) forests of western Canada has resulted in a landscape consisting of a mosaic of forest stands at different stages of mortality. Within forest stands, understory communities are the reservoir of the majority of plant species diversity and influence the composition of future forests in response to disturbance. Although changes to stand composition following beetle outbreaks are well documented, information on immediate responses of forest understory plant communities is limited. The objective of this study was to examine the effects of D. ponderosae-induced tree mortality on initial changes in diversity and productivity of understory plant communities. We established a total of 110 1-m² plots across eleven mature lodgepole pine forests to measure changes in understory diversity and productivity as a function of tree mortality and below ground resource availability across multiple years. Overall, understory community diversity and productivity increased across the gradient of increased tree mortality. Richness of herbaceous perennials increased with tree mortality as well as soil moisture and nutrient levels. In contrast, the diversity of woody perennials did not change across the gradient of tree mortality. Understory vegetation, namely herbaceous perennials, showed an immediate response to improved growing conditions caused by increases in tree mortality. How this increased pulse in understory richness and productivity affects future forest trajectories in a novel system is unknown.     

Decline in the Primary Productivity of Northwestern European Forests as a Consequence of Climate Aridization

Average annual age-dependent changes of carbon accumulation in the stemwood of major forest species (pine, spruce, and birch) of the taiga zone of the northwestern European Russia (Karelia) were analyzed. The changes in carbon accumulation were assessed by comparing carbon reserves in tree stands of various ages. Net primary productivity of photosynthesis (NPP) and the proportionality coefficient between respiratory decarboxylation and carbon reserves in wood were calculated. NPP clearly decreased with increasing climate aridization (aridity index). However, the time of the attainment of climax state by a stand did not depend on the latitudinal climate gradient. Hence, only the size of heterotrophic part of phytomass determines annual carbon losses in northern-taiga stands. It is concluded that the climate dependency of the long-term carbon storage in the phytomass of boreal forests is mainly determined by the climate effect on photosynthetic carbon sequestration.__________Translated from Fiziologiya Rastenii, Vol. 52, No. 4, 2005, pp. 513–517.Original Russian Text Copyright © 2005 by Voronin, Konovalov, Bolondinskii, Kaipiainen, Mao.     

Diverging climate trends in Mongolian taiga forests influence growth and regeneration of Larix sibirica

Central and semiarid north-eastern Asia was subject to twentieth century warming far above the global average. Since forests of this region occur at their drought limit, they are particularly vulnerable to climate change. We studied the regional variations of temperature and precipitation trends and their effects on tree growth and forest regeneration in Mongolia. Tree-ring series from more than 2,300 trees of Siberian larch (Larix sibirica) collected in four regions of Mongolia’s forest zone were analyzed and related to available weather data. Climate trends underlie a remarkable regional variation leading to contrasting responses of tree growth in taiga forests even within the same mountain system. Within a distance of a few hundred kilometers (140–490 km), areas with recently reduced growth and regeneration of larch alternated with regions where these parameters remained constant or even increased. Reduced productivity could be correlated with increasing summer temperatures and decreasing precipitation; improved growth conditions were found at increasing precipitation, but constant summer temperatures. An effect of increasing winter temperatures on tree-ring width or forest regeneration was not detectable. Since declines of productivity and regeneration are more widespread in the Mongolian taiga than the opposite trend, a net loss of forests is likely to occur in the future, as strong increases in temperature and regionally differing changes in precipitation are predicted for the twenty-first century.     

Effects of heterogeneity of pre-fire forests and vegetation burn severity on short-term post-fire vegetation density and regeneration in Samcheok,Korea

This study investigated the combined effects of heterogeneity of pre-fire forest cover and vegetation burn severity on post-fire vegetation density and regeneration at an early stage in Samcheok, Korea. To measure the spatial heterogeneity of pre-fire forests, spatial pattern metrics at a landscape level and class level were adopted, and a regression tree analysis for post-fire vegetation density and regeneration was used to avoid spatial autocorrelation. Two regression tree models were estimated for post-fire vegetation density and post-fire vegetation regeneration with the same independent variable sets, including heterogeneity of pre-fire forest cover and vegetation burn severity. The estimated model suggested that the percentage of Japanese red pine and burn severity were the most significant variables for post-fire vegetation density and regeneration, respectively. The compositional and spatial heterogeneity of pre-fire forest and burn severity, as well as the degree of burn severity, was found to have significant impacts on post-fire vegetation density and regeneration. Overall, more rapid vegetation regeneration can be expected in more severely burned areas. However, this rapid vegetation regeneration at an early stage is due mostly to perennials and shrubs, not to the sprouting or regrowth of trees. The study results strongly indicated that a susceptible forest cover type and its spatial patterns directly influence the heterogeneity of burn severity and early vegetation density and regeneration. Hence, the management of susceptible forest cover types is particularly critical for establishing more fire-resilient forests and for post-fire forest restoration.     

Stability in the patterns of long‐term development and growth of the Canadian spruce–moss forest

Aim The spruce–moss forest is the main forest ecosystem of the North American boreal forest. We used stand structure and fire data to examine the long‐term development and growth of the spruce–moss ecosystem. We evaluate the stability of the forest with time and the conditions needed for the continuing regeneration, growth and re‐establishment of black spruce (Picea mariana) trees. Location The study area occurs in Québec, Canada, and extends from 70°00′ to 72°00′ W and 47°30′ to 56°00′ N. Methods A spatial inventory of spruce–moss forest stands was performed along 34 transects. Nineteen spruce–moss forests were selected. A 500 m² quadrat at each site was used for radiocarbon and tree‐ring dating of time since last fire (TSLF). Size structure and tree regeneration in each stand were described based on diameter distribution of the dominant and co‐dominant tree species [black spruce and balsam fir (Abies balsamea)]. Results The TSLF of the studied forests ranges from 118 to 4870 cal. yr bp . Forests < 325 cal. yr bp are dominated by trees of the first post‐fire cohort and are not yet at equilibrium, whereas older forests show a reverse‐J diameter distribution typical of mature, old‐growth stands. The younger forests display faster height and radial growth‐rate patterns than the older forests, due to factors associated with long‐term forest development. Each of the stands examined established after severe fires that consumed all the soil organic material. Main conclusions Spruce–moss forests are able to self‐regenerate after fires that consume the organic layer, thus allowing seed regeneration at the soil surface. In the absence of fire the forests can remain in an equilibrium state. Once the forests mature, tree productivity eventually levels off and becomes stable. Further proof of the enduring stability of these forests, in between fire periods, lies in the ages of the stands. Stands with a TSLF of 325–4870 cal. yr bp all exhibited the same stand structure, tree growth rates and species characteristics. In the absence of fire, the spruce–moss forests are able to maintain themselves for thousands of years with no apparent degradation or change in forest type.     

Effects of Forest Age on Soil Autotrophic and Heterotrophic Respiration Differ between Evergreen and Deciduous Forests

We examined the effects of forest stand age on soil respiration (SR) including the heterotrophic respiration (HR) and autotrophic respiration (AR) of two forest types. We measured soil respiration and partitioned the HR and AR components across three age classes ∼15, ∼25, and ∼35-year-old Pinus sylvestris var. mongolica (Mongolia pine) and Larix principis-rupprechtii (larch) in a forest-steppe ecotone, northern China (June 2006 to October 2009). We analyzed the relationship between seasonal dynamics of SR, HR, AR and soil temperature (ST), soil water content (SWC) and normalized difference vegetation index (NDVI, a plant greenness and net primary productivity indicator). Our results showed that ST and SWC were driving factors for the seasonal dynamics of SR rather than plant greenness, irrespective of stand age and forest type. For ∼15-year-old stands, the seasonal dynamics of both AR and HR were dependent on ST. Higher Q₁₀ of HR compared with AR occurred in larch. However, in Mongolia pine a similar Q₁₀ occurred between HR and AR. With stand age, Q₁₀ of both HR and AR increased in larch. For Mongolia pine, Q₁₀ of HR increased with stand age, but AR showed no significant relationship with ST. As stand age increased, HR was correlated with SWC in Mongolia pine, but for larch AR correlated with SWC. The dependence of AR on NDVI occurred in ∼35-year-old Mongolia pine. Our study demonstrated the importance of separating autotrophic and heterotrophic respiration components of SR when stimulating the response of soil carbon efflux to environmental changes. When estimating the response of autotrophic and heterotrophic respiration to environmental changes, the effect of forest type on age-related trends is required.     

Soil microbial biomass carbon and nitrogen in forest ecosystems of Northeast China: a comparison between natural secondary forest and larch plantation

Aims Natural secondary forest (NSF) and larch plantation are two of the predominant forest types in Northeast China. However, how the two types of forests compare in sustaining soil quality is not well understood. This study was conducted to determine how natural secondary forest and larch plantation would differ in soil microbial biomass and soil organic matter quality.Methods Microbial biomass carbon (MBC), microbial biomass nitrogen (MBN), soil organic carbon (SOC) and total nitrogen (TN) in the 0- to 15-cm and 15- to 30-cm soil layers were investigated by making chemical and biological measurements in the montane region of eastern Liaoning Province, Northeast China, during the growing season of 2008 in stands of NSF and Larix olgensis plantation (LOP).Important findings We found that soil MBC and MBN were significantly lower in the LOP than in the NSF. Both MBC and MBN declined significantly with increasing soil depth in the two types of stands. The ratios of MBC to SOC (MBC/SOC) and MBN to TN (MBN/TN) were also significantly lower in the LOP than in the NSF. Moreover, the values of MBC, MBC/SOC, and MBN/TN significantly varied with time and followed a similar pattern during the growing season, all with an apparent peak in summer. Our results indicate that NSF is better in sustaining soil microbial biomass and nutrients than larch plantation in the temperate Northeast China. This calls for cautions in large-scale conversions of the native forests to coniferous plantations as a forest management practice on concerns of sustaining soil productivity.     

Species-specific growth-climate responses of Dahurian larch (Larix gmelinii) and Mongolian pine (Pinus sylvestris var. mongolica) in the Greater Khingan Range,northeast China

Responses of tree growth to climate are usually spatially heterogeneous. Besides regionally varying external environments, species specificity is a crucial factor in determining said spatial heterogeneity. A better understanding of this species specificity would improve our estimations of the warming effects on forests. In this study, we selected two widely-distributed boreal conifers, Dahurian larch (Larix gmelinii) and Mongolian pine (Pinus sylvestris var. mongolica), to compare their growth-climate responses, including long-term growth-climate correlations and short-term growth resilience to drought. We sampled 160 trees and 481 tree-ring cores from the two species in two pure and two mixed forests, located in the Greater Khingan Range, northeast China. We found that Dahurian larch was generally positively correlated with spring temperature and negatively correlated with summer temperature. In contrast, Mongolian pine was more sensitive to summer moisture. Our results suggest that the main climatic limitations were low spring temperatures for Dahurian larch and summer moisture deficits for Mongolian pine. Dahurian larch represented higher growth resistance to drought, while Mongolia pine represented higher recovery. Based on this, we inferred that Dahurian larch was more vulnerable to extreme droughts, while Mongolian pine was more vulnerable to frequent droughts. We also demonstrated the effects of forest type on growth-climate responses. The negative effects of summer temperatures on Mongolian pine seemed to be more significant in mixed forests. As warming continued, Mongolian pine in this area would suffer severer moisture deficits, especially when coexisting with Dahurian larch. Our results suggest that Dahurian larch gained an advantage in the competition with Mongolian pine during high moisture stress. Driven by the warming trends, the species specificity in growth response would ultimately promote the separation of the two species in distribution. This study will help improve our estimations of the warming effects on forests and develop more species-targeted forest management practices.     

Reserves of carbon in the organic matter of postfire pine forests in the southwest of the Baikal region

A change in the mass and composition of organic matter in the phytomass and soil of pine forests affected by mid-intensity and high-intensity fires is considered. It is shown that a mid-intensity fire did not catastrophically affect the pool of carbon in the middle-aged pine forests of the subtaiga forest-steppe and the taiga higher belt areas in the southwest of the Baikal region. Five years after a high-intensity fire, the carbon reserves in a mature taiga pine forest remain 20% lower than in an unaffected pine forest. Compared with the reference figures, the mass of C and soil cover in the stand phytomass decreased by 18 and 63%, respectively. In the easily mineralizable fraction of organic matter, the reserves of carbon decreased by half owing to burnout of waste wood (by 64%) and root detritus (by 50% compared with the reference tree stand figures).     

Spatial distribution and temporal dynamics of high‐elevation forest stands in southern Siberia

Aim To evaluate the hypothesis that topographic features of high‐elevation mountain environments govern spatial distribution and climate‐driven dynamics of the forest. Location Upper mountain forest stands (elevation range 1800–2600 m) in the mountains of southern Siberia. Methods Archive maps, satellite and on‐ground data from1960 to 2002 were used. Data were normalized to avoid bias caused by uneven distribution of topographic features (elevation, azimuth and slope steepness) within the analysed area. Spatial distribution of forest stands was analysed with respect to topography based on a digital elevation model (DEM). Results Spatial patterns in mountain forests are anisotropic with respect to azimuth, slope steepness and elevation. At a given elevation, the majority of forests occupied slopes with greater than mean slope values. As the elevation increased, forests shifted to steeper slopes. The orientation of forest azimuth distribution changed clockwise with increase in elevation (the total shift was 120°), indicating a combined effect of wind and water stress on the observed forest patterns. Warming caused changes in the forest distribution patterns during the last four decades. The area of closed forests increased 1.5 times, which was attributed to increased stand density and tree migration. The migration rate was 1.5 ± 0.9 m year^–1, causing a mean forest line shift of 63 ± 37 m. Along with upward migration, downward tree migration onto hill slopes was observed. Changes in tree morphology were also noted as widespread transformation of the prostrate forms of Siberian pine and larch into erect forms. Main conclusions The spatial pattern of upper mountain forests as well as the response of forests to warming strongly depends on topographic relief features (elevation, azimuth and slope steepness). With elevation increase (and thus a harsher environment) forests shifted to steep wind‐protected slopes. A considerable increase in the stand area and increased elevation of the upper forest line was observed coincident with the climate warming that was observed. Warming promotes migration of trees to areas that are less protected from winter desiccation and snow abrasion (i.e. areas with lower values of slope steepness). Climate‐induced forest response has significantly modified the spatial patterns of high‐elevation forests in southern Siberia during the last four decades, as well as tree morphology.     

Landscape context of plantation forests in the conservation of tropical mammals

Plantation forests have been expanding in many tropical and subtropical environments. Howerver, even when they replace less wildlife friendly land uses such as pastures and annual crops, the biodiversity levels of pristine natural habitats often have not been recovered. Here we addressed how the landscape context of plantation forests located in South-eastern Brazil affects species richness and community resilience of medium and large size mammals. The area covered by native habitat fragments surrounding plantation forests is positively related to functional richness, including the presence of species more vulnerable to extinction in fragmented landscapes. In addition, the degree of aggregation of plantation forest stands is negatively related to more vulnerable species. No primates were recorded in our seven plantation forest sites (ranging from 272 to 24,921 ha), even when they were seen in native habitat fragments adjacent to commercial tree stands. Two invasive species (Sus scrofa and Lepus capensis) were recorded in four plantation forest sites. The impoverishment of fauna in plantation forests is due to two factors. First, plantation forests generally are structurally simplified habitats when compared to highly diverse tropical forests. Secondly, the isolation from habitat fragments which act as source of individuals in the landscape precludes the establishment of individual in plantation forest. We also highlighted the management practices to improve the complexity of vegetation in commercial tree stands should be taken cautiously, insofar as reduced productivity per area entails a greater demand for land. Thus, an alternative would be intensify the management of the commercial tree stands for wood production together with the restoration of adjacent areas set aside to conservation and native habitat fragments protection.