Stability Of Forest Ecosystems Research Articles

Effect of Forest Fires on the Alpha and Beta Diversity of Soil Bacteria in Taiga Forests: Proliferation of Rare Species as Successional Pioneers

Forest fires are among the most influential drivers of changes in forest soil bacterial diversity. Nevertheless, little is known regarding the effects of forest fires on maintaining the complex interactions that preserve forest ecosystem stability. Therefore, this study characterized alterations in soil bacterial community composition and diversity within taiga forests subjected to varying disturbance intensities. Particularly, this study examined the bacterial community within a Larix gmelinii fire-burnt site in Daxinganling, analyzing the changes in bacterial community structure and function across light, moderate, and heavy fire-burnt sites, as well as a control sample site, utilizing Illumina MiSeq technology. Through an assessment of bacterial community diversity and soil physicochemical properties (moisture content (MC), pH, microbial biomass carbon (MBC), organic carbon (SOC), total nitrogen (TN), available nitrogen (AN), available phosphorus (AP), and available potassium (AP)), we explored the influence of the soil microenvironment on the soil bacterial community structure at the burnt site under different disturbance intensities. Our findings demonstrated that (1) there was no significant change in the Chao index of soil bacteria in the burnt site under different disturbance intensities, whereas the Shannon index decreased significantly (p < 0.05) and the Simpson index increased significantly (p < 0.05) in the burnt site under light and moderate disturbance. (2) The relative abundance of dominant phyla, such as Proteobacteria, Proteobacteria, and Actinobacteriota, did not change significantly in the fire-burnt site under different disturbance intensities, whereas rare species, such as Acidipila, Occallatibacter, and Acidibacter, experienced a significant increase in relative abundance at the genus level. (3) The results of principal coordinates analysis (PCoA) and canonical correlation analysis (CCA) revealed significant differences in the Beta diversity of soil bacteria in the fire-burnt site under varying interference intensities. The Beta diversity of soil bacteria exhibited significant differences (p = 0.001), with MC, pH, TN, AN, and AK identified as significant influencing factors. (4) FAPROTAX functional prediction analyses were conducted to assess the changes in soil bacteria involved in Cellulolysis, Chemoheterotrophy, and Aerobic_Chemoheterotrophy in the fire-burnt site, with the relative abundance of bacteria involved in Chemoheterotrophy being significantly increased (p < 0.05) under different disturbance intensities. Collectively, our findings demonstrated that different disturbance intensities caused by fires significantly affected the Alpha diversity, Beta diversity, and functional abundance of soil bacterial communities in taiga forests, with MC, pH, TN, AN, and AK being identified as key influencing factors. Additionally, the presence of numerous rare species suggests their role as pioneer communities in the succession of soil bacterial communities.

Effects of Seed Size and Cache Density on the Seed Fate of Quercus wutaishanica Mediated by Rodents.

Animal-mediated seed dispersal is very important for plant population regeneration and the stability of forest ecosystems. Seed size and cache density are important factors for seed dispersal, but we still know little about seed size selection at different cache densities. Here, we conducted field experiments in a Larix principis-rupprechtii plantation in the Liupan Mountains in Ningxia province to investigate the effects of tag-marked Quercus wutaishanica seeds of different sizes and cache densities on predation and the scatter-hoarding behavior of rodents. The results showed lower proportions of intact in situ (IIS) and eaten in situ (EIS) large seeds than small seeds at all levels of cache density, with the exception of IIS seeds at a 6.25 seed·m-2 cache density. A higher proportion of small seeds were eaten after removal (EAR), but a higher proportion of large seeds were scatter-hoarded (SH) by rodents at most cache densities. Furthermore, rodents preferentially removed large seeds farther away for eating or scatter-hoarding. The IIS and EIS proportions of both large and small seeds declined, but the proportion of the two types of seeds that were EAR fluctuated, increasing with increasing cache density. Rodents preferred to increase the proportion of scatter-hoarding of large seeds with increasing cache density, whereas the proportion of scatter-hoarding of small seeds was maximized at a cache density of 6.25 seed·m-2. Both the eaten distance after removal (EDAR) and scatter-hoarded distance (SHD) increased with increasing cache density. These results suggest that large seeds are more likely to be scatter-hoarded and removed to longer distances than small ones. Rodents tended to reduce the seed proportion of EIS seeds and increased the proportion of seeds EAR and SH, and accordingly increased EDAR and SHD with increasing cache density. This study provides some scientific basis for animal-mediated seed dispersal.

Co-Occurrence Patterns of Soil Fungal and Bacterial Communities in Subtropical Forest-Transforming Areas.

Soil microbial communities are engineers of important biogeochemical processes and play a critical role in regulating the functions and stability of forest ecosystem. However, few studies have assessed microbial interactions during forest conversion, which is essential to the understanding of the structure and function of soil microbiome. Herein, we investigated the co-occurrence network pattern and putative functions of fungal and bacterial communities in forest-transforming areas (five sites that cover the typical forests) using high-throughput sequencing of the ITS genes and 16S rRNA. Our study showed that the bacterial network had higher average connectivity and more links than fungal network, which might indicate that the bacterial community had more complex internal interactions compared with fungal one. Alphaproteobacteria_unclassfied, Telmatobacter, 0319-6A21 and Latescibacteria_unclassfied were the keystone taxa in bacterial network. For the fungal community network, the keystone taxon was Ceratobasidium. A structural equation model indicated that the available potassium and total organic carbon were important soil environmental factors, which affected all microbial modules, including bacterial and fungi. Total nitrogen had significant effects on the bacterial module that contains a relatively rich group of nitrogen cycling functions, and pH influenced the bacterial module which have higher potential functions of carbon cycling. And, more fungal modules were directly affected by forest structure (S Tree) compared with bacterial ones. This study provides new insights into our understanding of the feedback of underground creatures to forest conversion and highlights the importance of microbial modules in the nutrient cycling process.

Vertical distribution characteristics of soil organic carbon and vegetation types under different elevation gradients in Cangshan, Dali.

The Cangshan National Nature Reserve of Dali City was adopted as the research object to clarify the vertical distribution characteristics of soil organic carbon (SOC) and vegetation types at different elevations in western Yunnan. The contents of SOC, light fraction organic carbon (LFOC), heavy fraction organic carbon (HFOC), and water-soluble organic carbon (WSOC) in the 0-30 cm soil layer at different elevations (2,400, 2,600, 2,800, 3,000, 3,200, 3,400, and 3,600 m) were determined, and the above-ground vegetation types at different elevations were investigated. Results showed that the SOC content was the highest in 0-20 cm surface soil and gradually decreased with the deepening of the soil layer. It increased then decreased with the increase in elevation, and it peaked at 3,000 m. The LFOC content was between 1.28 and 7.3515 gkg-1. It exhibited a decreasing trend and little change in profile distribution. The HFOC content ranged between 12.9727 and 23.3708gkg-1; it increased then decreased with the increase in profile depth. The WSOC content was between 235.5783 and 392.3925 mgkg-1, and the response sensitivity to elevation change was weak. With the increase in elevation, WSOC/SOC and LFOC/SOC showed a similar trend, whereas HFOC presented an opposite trend. This observation indicates that the active organic carbon content at 3,600 m was lower than that at 2,400 m, and the middle elevation was conducive to the storage of active organic carbon. Meanwhile, the physical and chemical properties of soil affected the distribution of organic carbon to a certain extent. The vegetation type survey showed that the above-ground dominant species within 2,400-2,800 m were Pinus yunnanensis and Pinus armandii. Many evergreen and mixed coniferous broadleaf forests were distributed from 3,000 m to 3,200 m. Species of Abies delavayi were mainly distributed from 3,400m to 3,600m. This research serves as a reference for the study of forest soil carbon stability in high-elevation areas and plays an important role in formulating reasonable land use management policies, protecting forest soil, reducing organic carbon loss, and investigating the carbon sequestration stability of forest ecosystems.

Effect of forest planting patterns on the formation of soil organic carbon during litter lignocellulose degradation from a microbial perspective.

Litter decomposition is an important source of soil organic carbon, and it plays a key role in maintaining the stability of forest ecosystems. The microbial mechanism of soil organic carbon (SOC) formation in different urban forest planting patterns during litter lignocellulose degradation is still unclear. The key genes, microbes, and metabolites in the process of lignocellulose degradation and SOC formation were determined by metagenomics and metabolomics in different litter decomposition layers and soil layers in different urban forest planting patterns, including three types of broadleaf forests (BP forests), three types of coniferous forests (CP forests), and two types of mixed coniferous and broadleaf forests (MCBP forests). The results indicated that the cellulose, hemicellulose, and lignin concentrations from the undecomposed layer to the totally decomposed layer decreased by 70.07, 86.83, and 73.04% for CP litter; 74.30, 93.80, and 77.55% for BP litter; and 62.51, 48.58, and 90.61% for MCBP litter, respectively. The soil organic carbon of the BP forests and MCBP forests was higher than that of the CP forests by 38.06 and 94.43% for the 0-10 cm soil layer and by 38.55 and 20.87% for the 10-20 cm soil layer, respectively. Additionally, the gene abundances of glycoside hydrolases (GHs) and polysaccharide lyases (PLs) in the BP forests were higher than those in the MCBP forests and CP forests. Amino acid metabolism, sugar metabolism, TCA metabolism, and cAMP signaling metabolism were mainly between the CP forests and BP forests, while the TCA cycle, pyruvate metabolism, phenylalanine metabolism, and tyrosine metabolism were mainly between the BP forests and MCBP forests during litter decomposition. Additionally, ammonia nitrogen and hemicellulose were key factors driving SOC formation in the CP forests, while ammonia nitrogen, hemicellulose, and lignocellulose-degrading genes were key factors driving SOC formation in the BP forests. For the MCBP forests, cellulose, pH, ammonia nitrogen, and lignin were key factors driving SOC formation. Our findings revealed that the BP forests and MCBP forests had stronger lignocellulose degradation performance in the formation of SOC. This study provided a theoretical basis for the flow and transformation of nutrients in different urban forest management patterns.

Does ash dieback affect the reproductive ecology of Fraxinus excelsior L.?

Forest tree species reproduction is a key factor in maintaining the genetic diversity of future generations and the stability of forest ecosystems. The ongoing ash dieback disease could affect the reproductive ecology of Fraxinus excelsior L. and have a major impact on the quantity and quality of pollen and seeds. In this study, we investigated pollen production and viability of pollen and seeds of ash trees with different health status from 2018 to 2022. Inflorescences were collected from 105 trees (pollen production), pollen from 125 trees (pollen viability), and seeds from 53 trees (seed quality) in two seed orchards and in one floodplain forest in southern Germany. Not all parameters were examined at every site every year. The average pollen production per tree was estimated at 471.2 ± 647.9 billion pollen grains. In addition, we found that a high number of inflorescences did not equate to high pollen production per inflorescence. Pollen production of healthy and diseased trees did not differ significantly, although only 47% of severely diseased male trees (vs. 72% for healthy trees) produced flowers. With regards to pollen viability, the TTC test showed an average viability of 73% ± 17%. Overall, there was a slight tendency for diseased trees to have less viable pollen. However, a significant difference could only be calculated for trees in the floodplain forest. The percentage of germinable seeds in 2018 was 38% in the floodplain forest and 57% in one of the seed orchards. The percentage of viable seeds (TTC test) ranged from 17 to 22% in the orchards in 2020. Non-viable seeds were usually heavily infested by insects. In general, seed quality was not significantly different between healthy and diseased trees. Our results indicate that ash dieback affects flower formation and pollen viability but not pollen production or seed quality. Nevertheless, the fact that hardly any flowering was observed, especially for trees that were seriously affected, suggests a negative effect of ash dieback on reproductive performance. Thus, severely diseased trees will transfer their genes to a smaller extent to the next generation.

Regeneration dynamics in mixed mountain forests at their natural geographical distribution range in the Western Rhodopes

Mixed mountain forests consisting of Norway spruce (Picea abies (L.) Karst.), European beech (Fagus sylvatica L.), and silver fir (Abies alba Mill.) are among the most productive and stable forest ecosystems in Europe. Their southeasternmost geographical distribution range is located in the Western Rhodopes, where they have high economic, recreational, and ecological value. In the past, shelterwood cuttings dominated forest management practices in these forests and were mainly aimed at maintaining and reproducing conifers. During the past two decades, single-tree and group-tree selection systems have been promoted as alternative management approaches to support the conversion of spruce-dominated stands to close-to-nature mixed forests of fir, beech, and spruce. However, the natural regeneration dynamics in these stands are barely known, and their dependence on microsite and management effects needs to be better understood.The objective of this study was to investigate ecological factors under management regimes of different intensity (“single-tree”-selection and “group-tree”-selection) that influence the regeneration processes in mixed mountain forests in the Bulgarian Rhodopes. Data on regeneration and microsite conditions were collected on 105 systematically distributed plots (25 m2/100 m2) in four 100–120 years old stands located in the regional forest district of Smoljan, Bulgaria (1580–1650 m a.s.l.). We relied on generalizeds linear mixed models to analyse for each species the (1) size-dependent regeneration density and (2) height increment in dependence on management practices, competing vegetation, as well as soil and light conditions.Our study revealed an overall high potential for recruitment in the Western Rhodopes. Regeneration density was highest in fir (median 12800 N ha-1), followed by spruce (median 1600 N ha-1) and beech (median 1200 N ha-1). Fir benefited most from “single-tree” selection cuttings, while “group-tree” selection cutting tended to promote beech and fir but also spruce. Competing ground vegetation was detrimental for seedling density of all species. Annual height increment increased with plant size, was lowest in spruce, and similar in fir and beech. Sapling increment was driven by light, whereas seedlings did not react to increased radiation. Browsing was species-specific and was highest in beech (15–30 %), followed by fir (5–10 %) and spruce (<1 %). It was not a crucial factor in impeding tree recruitment. We conclude that frequent harvest activities of low intensity which consider advanced regeneration are a promising approach to successfully convert the formerly spruce-fir-dominated forests to climate-adapted fir-beech-(spruce)-mixed stands.

Response of radial growth of Pinus sylvestris var. mongolica of different stand ages to climate and extreme drought events in the semi-arid region of western Liaoning, Northeast China

The frequency and severity of drought events are increasing under a changing climate, trees of different stand ages respond differently to drought events, which has a great impact on the stability of forest ecosystems. In this study, we measured radial growth (RG) in cored trees from 49 forests including young stands (20–30a) and middle-aged stands (31–50a) of Pinus sylvestris var. mongolica plantations in a semi-arid area of western Liaoning, China. We evaluated the response of RG of P. sylvestris to long-term climate, and calculate three response indicators: resistance (Rt), recovery (Rc) and resilience (Rs), so as to measure the growth response of trees to drought events. Results showed that a negative correlation was detected between RG of young stands and the monthly highest temperature (MHT) in April and May. Positive correlations were found between RG of young stands and the monthly lowest temperature (MLT) across periods from September to November, when RG of young stands was also positively correlated with Palmer Drought Severity Index (PDSI) across whole-years. There was a positive correlation between RG of middle-aged stands and MLT in September, and PDSI from June to December. After the first drought event, most pine trees recovered their RG (Rc &amp;gt; 1, Rs &amp;gt; 1). However, after three consecutive drought events, Rt, Rc, and Rs of pine trees decreased significantly (p &amp;lt; 0.05), and Rt and Rs were less than 1. In summary, younger pine trees are more sensitive to climate change, and spring drought is more inhibitory to growth of pine trees than high summer temperatures. Pine trees have a compensation effect after experiencing drought events, but the cumulative effect of multiple drought events will gradually offset the compensation effect of trees and eventually decline in pine tree growth, while the resistance and resilience of young stands after continuous drought events were significantly lower than those of middle-aged stands, and have a higher risk of death.

Analysis of Specific Ecological and Genetic Soil Properties for the Forest Ecosystem Monitoring in the Zone of Coniferous–Broadleaved Forests

A reliable assessment of the composition and properties of soils in forest ecosystems is the basis for environmental monitoring, including monitoring of carbon pools and fluxes, which is of particular importance in the context of global changes in the environment and climate. The specific ecological and genetic features and classification of soils are analyzed at permanent monitoring sites in the main types of forest ecosystems of the Zvenigorod Biostation of Moscow State University and the Sima Quarry state nature reserve (Moscow oblast, Russia). Soil monitoring is organized and conducted on the basis of national experience and recommendations of the International Cooperative Programme on Assessment and Monitoring of Air Pollution Effects on Forests (ICP Forests). The eluvozems and soddy eluvozems on two-layered deposits predominate in the soil cover of the nature reserve; these soils have a loamy sandy texture (content of clay fraction of <0.002 mm is 3.3–7.0%), acidic media ({text{p}}{{{text{H}}}_{{{{{text{H}}}_{{text{2}}}}{text{O}}}}} 4.6–5.7), low cation exchange capacity, low content of exchangeable bases (30–52 cmolс/kg in organic and 0.6–7.5 cmolс/kg in mineral horizons), and low base saturation (49–67 and 11–51%, respectively). The contents of potentially toxic metals (Pb, Cd, Cu, Ni, and Zn) in the soils of the nature reserve do not exceed background levels. The ecological state of soils assessed according to their chemical and physical properties improves in the following order: contact-bleached eluvozem—pseudofibrous soddy eluvozem—ferruginous soddy eluvozem. This determines the functioning and stability of forest ecosystems to external impacts under increasing anthropogenic pressure and climate change.

Soil horizons regulate bacterial community structure and functions in Dabie Mountain of the East China

Soil bacterial communities regulate nutrient cycling and plant growth in forests. Although these bacterial communities vary with soil nutrients and plant traits, the variation and degree with soil horizons in different forest types remain unclear. Here, bacterial communities of 44 soil samples from organic horizon (O horizon) and mineral horizon (M horizon) of three forest types (Cunninghamia, broad-leaved and Pinus forests) in subtropical forests of Dabie Mountain, China were analyzed based on amplicon sequencing. We assessed the effects of soil horizons and forest types on bacterial communities. The results showed that the bacterial richness and diversity were significantly higher in the O horizon than in the M horizon. Furthermore, the bacterial community composition and functions were also remarkably different between the two soil horizons. Furthermore, forest types could affect bacterial community composition but not for diversity and functions. Moreover, soil organic matter, including the total organic carbon, available phosphorus, total organic nitrogen, available potassium, ammonium nitrogen, and pH were main drivers for bacterial community composition. The results propose robust evidence that soil horizons strongly driven bacterial community composition and diversity, and suggest that microhabitat of soil bacterial communities is important to maintain the stability of forest ecosystem.

Selective logging destabilizes the functioning and composition of forest ecosystems at multiple spatial scales

Selective logging is one of the most prevalent land uses of forests worldwide, affecting biodiversity and ecosystem functioning. However, the effect of selective logging on the dual nature of temporal stability, and the scale dependence of this effect, remain to be elucidated. By conducting several decade‐long experiments in temperate forest ecosystems, we tested the effects of selective logging on aggregate and compositional stability at multiple spatial scales. As expected, forest ecosystem stability at larger spatial scales was enhanced both by the stability of local scales (i.e. α stability) and asynchronous dynamics among local communities (i.e. spatial asynchrony). We found that the negative effects of selective logging on both facets of forest stability propagated from local to larger spatial scales due to reduced α stability and the biological insurance effects of α diversity. However, both spatial aggregate and compositional asynchrony were not affected by selective logging. Interestingly, despite the selective logging, α diversity still provided biological insurance effects for maintaining aggregate and compositional stability. Our results imply that selective logging may destabilize the aggregate ecosystem functioning and species composition of forest ecosystems at local and larger spatial scales. To our knowledge, this study provides the first evidence of the scale dependence of aggregate and compositional stability of forest ecosystems in response to selective logging. Our findings suggest that forest management should avoid excessive selective logging and strive to protect forest diversity to safeguard the sustainability of the functioning and composition of natural forest ecosystems at multiple spatial scales.Keywords: aggregate stability, compositional stability, diversity, ecosystem functioning, spatial asynchrony, stability

The key role of ecological resilience in radial growth processes of conifers under drought stress in the subalpine zone of marginal deserts

Global climate change is exacerbating drought pressure on forests. However, the response patterns and physiological mechanisms of conifer species to drought, specifically in terms of radial growth, ecological resilience and soil water utilization, are not clearly understood. This study aims to quantify the effects of resilience on radial growth and identify the role of soil moisture utilization strategies in the resilience of species under drought intensities. We focus on two conifer species, Picea crassifolia (spruce) and Pinus tabuliformis (pine), located on the southern edge of the Tengger Desert in northwestern China. The dynamics of radial growth and ecological resilience were identified, and the seasonal growth rates of species based on soil water were simulated using the VS-oscilloscope model under varying drought stress. The results showed that spruce growth and recovery contributed by soil water were suppressed with frequent severe droughts, leading to a decline in growth (−0.5 cm2 year−1/10a, p < 0.05), despite its greater resistance to mild and moderate drought (−4.63 %). However, pine exhibited a stronger recovery (+40.25 %, p < 0.05) and higher variation in growth (−0.3 cm2 year−1/10a, p < 0.05) under soil moisture stress, despite its weaker resistance to drought (−23.53 %, p < 0.05). These findings provide insights into the growth, resilience, and water adaptation mechanisms of species under drought events, and theoretical support for the conservation and management of conifer diversity and forest ecosystem stability in climate-sensitive regions.

Long-term marine protection enhances kelp forest ecosystem stability.

Trophic downgrading destabilizes ecosystems and can drive large-scale shifts in ecosystem state. While restoring predatory interactions in marine reserves can reverse anthropogenic-driven shifts, empirical evidence of increased ecosystem stability and persistence in the presence of predators is scant. We compared temporal variation in rocky reef ecosystem state in New Zealand's oldest marine reserve to nearby fished reefs to examine whether protection of predators led to more persistent and stable reef ecosystem states in the marine reserve. Contrasting ecosystem states were found between reserve and fished sites, and this persisted over the 22-year study period. Fished sites were predominantly urchin barrens but occasionally fluctuated to short-lived turfs and mixed algal forests, while reserve sites displayed unidirectional successional trajectories toward stable kelp forests (Ecklonia radiata) taking up to three decades following protection. This provides empirical evidence that long-term protection of predators facilitates kelp forest recovery, resists shifts to denuded alternate states, and enhances kelp forest stability.

Driving mechanisms of productivity stability vary with selective harvesting intensities in a mixed broad-leaved Korean pine forest

Key messageWe found that the stabilizing mechanisms for forest productivity varied across harvesting intensities in a mixed broad-leaved Korean pine forest. Effects of overyielding at high species richness and species asynchrony occurred only in unharvested and lightly harvested plots, whereas asymmetries between individuals of different size contributed significantly to stabilizing productivity when harvestings became intensive.ContextUnderstanding the driving factors of forest ecosystem stability has become increasingly crucial in forest management. However, it remains unclear whether and how the stabilizing mechanisms of forest productivity might be influenced by management practices.AimsWe related the temporal stability of aboveground biomass productivity to harvesting history. We further tested how three key driving mechanisms of stability might be modulated by selective harvesting intensities.MethodsBased on a 10-year monitoring (five repeated tree inventories) of a mixed broad-leaved Korean pine forest in Northeastern China recovering from selective harvesting, we examined the relative importance of two diversity-dependent mechanisms (overyielding and species asynchrony) and one size-dependent mechanism (asymmetric growth) for productivity stability across a wide range of intensities (0–73.4% basal area removed).ResultsWe found that selective harvesting significantly lowered the productivity stability, species asynchrony, and growth dominance coefficient. Growth dominance coefficient had an overall stronger effect on stability than species richness and asynchrony. Moreover, the strengths of stabilizing mechanisms varied across harvesting intensities: effects of overyielding at high species richness and species asynchrony were detected only in unharvested and lightly harvested plots, whereas the explanatory power of growth dominance coefficient outweighed the diversity-related variables when harvesting became intensive.ConclusionsWe emphasized the importance to consider both diversity- and size-related explanatory variables as potential mechanisms for the temporal stability of forest productivity. In fact, how growth is partitioned among trees of different species as well as sizes may co-determine the response of forest stability to disturbances.

State and Stability of Forest Ecosystems of the Region with Extreme Anthropogenic Transformation (Evidence from the Oka River Basin)

State and Stability of Forest Ecosystems of the Region with Extreme Anthropogenic Transformation (Evidence from the Oka River Basin)

ECOLOGICAL RESOURCES OF BOREAL FORESTS IN ABSORPTION OF GREENHOUSE GASES AND IN ADAPTATION TO GLOBAL WARMING (TO THE PARIS AGREEMENT ON CLIMATE CHANGE)

On the example of the forests of the Oka basin, an experiment was carried out to numerically solve the dual task set by the Paris (2015) Agreement on climate change: to assess the absorption of CO2 from the atmosphere by forest communities under current global warming and their adaptation to climate change. With the help of empirical-statistical modeling, the mechanisms of forest cover regulation of the carbon cycle are revealed, with the effect of mitigating the predicted warming. Assessments of the adaptive potential of forests and its role in carbon adsorption and conservation have been carried out. The proposed index of elastic-plastic functional stability of forest ecosystems was used as an indicator of adaptation. The role of forest sustainability as a direct environmental factor in the absorption of greenhouse gases has been statistically established. An unambiguous picture of a significant increase in the ecological resources of boreal and nemoral forests has been obtained – their adsorption capacity with an increase in adaptive potential. It has been established that during the predicted 100-year period, the overall elastic-plastic stability of forest formations in the region should increase, especially at the current rate of global warming. Due to this, a significant increase in the ability of boreal and, to a lesser extent, nemoral forests to absorb greenhouse gases should also be expected. The obtained results of regional predictive modeling demonstrate the effectiveness of the coupled study of the adsorption capacity of forest biomes and their adaptation to a changing climate.

Scenario Approach to Adaptation of Forest Ecosystems in the Russian Federation under Climate Change

Correlations between the quantitative values of abiotic factors associated with climate change and the criteria for the vulnerability of forest ecosystems for 24 model subjects of the Russian Federation have been established. A high degree of closeness of the relationship between climatic parameters and forest fires was revealed for forest ecosystems in the Center and the South of Russia, as well as Eastern Siberia. Using a matrix model for positioning the adaptive potential of a single regional forest ecosystem, clusters with the most vulnerable to climate change groups of regional forest ecosystems were identified. The application of the developed methodology for the analysis of regional complexes of forest ecosystems made it possible to establish that there is a shift in the indicators of their adaptive potential to the lower limit of their sustainability (Arkhangelsk, Leningrad, Voronezh, Tyumen, Irkutsk oblasts, Khanty-Mansi Autonomous Okrug, Khabarovsk krai). Based on the study and clustering of model federal subjects according to the level of adaptive potential, differentiation of management decisions and forestry measures for enlarged territorial objects, including various federal subjects, was carried out in order to maintain and strengthen the adaptive potential of forest ecosystems. Measures for adapting forest ecosystems to climate change can be implemented in the context of three scenarios: forest management with elements of reactive adaptation to climate change for stable forest ecosystems, implementation of the forestry adaptation strategy to climate change for unstable forest ecosystems and restoration and maintenance of ecosystem functions of forests for degrading forest ecosystems.

Effects of Drought and Flooding on Growth and Physiology of Cinnamomum camphora Seedlings

In the context of climate change, future patterns of precipitation are expected to increase the intensity and frequency of drought and flooding stress. This is also likely to result in more frequent flooding–drought alternation events. Drought and flooding stress can have negative effects on tree morphology, physiology, and biochemistry, which can potentially pose long-term threats to tree survival and further disrupt the stability of forest ecosystems. However, it remains unclear how trees would cope with these stressors and their alternations through growth and physiology responses. Potted seedlings of C. camphora were grown under a rainout shelter in the field with four water treatments for 40 days: well-watered (WW), drought stress (DS), flooding stress (FS) and flooding–drought alternation (FDF). Growth, leaf gas exchange, water potential, and biochemical traits were measured. Results show different seedling growth patterns under drought and flooding stress. Drought increased the root-to-shoot ratio (+25%) but flooding favored leaf growth (+33%). Decreases in photosynthesis under drought and flooding were mainly related to stomatal limitations, accompanied by abscisic acid accumulation under drought but not under flooding. Drought reduced water potential, and flooding–drought alternation only decreased water potential in its drought phase. Flooding treatment had no effect on water potential. Drought treatment increased the proline concentrations (+74%) and carbon isotopic composition (+3.7%), but all treatments had no effect on the concentrations of elements in leaves. Drought stress led to carbon depletion in both stem and root, whereas flooding stress primarily induced carbon depletion in the root. Flooding–drought alternation was accompanied by complex physiological responses, including physiological recovery when the stress (flood, drought) was relieved. Our results have shown the different effects of drought and flooding on the growth and physiology of C. camphora seedlings, emphasizing the need to consider specific water stress conditions in future studies and providing a theoretical basis for better management of this tree species in urban areas under variable rainfall patterns.

Ecological Resources of Boreal Forests for Greenhouse Gas Absorption and in Adaptation to Global Warming (for the Paris Climate Change Agreement)

The forests of the Oka basin were used as an example in an experiment to solve numerically the dual-purpose task set by the Paris Climate Change Agreement (2015): to assess CO2 absorption from the atmosphere by forest communities under the current global warming and forest adaptation to climate change. The regulation processes of the carbon cycle by the forest cover, with the effect of mitigating the predicted warming, were revealed with the help of empirical–statistical modeling. The adaptation potential and role of forests in carbon adsorption and conservation were assessed. The proposed index of elastic–plastic functional stability of forest ecosystems was used as an adaptation indicator. Forest sustainability as a direct environmental factor in greenhouse gas absorption was estimated in statistical terms. An unambiguous idea of the significant increase in the ecological resources of boreal and nemoral forests was obtained: their adsorption capacity increased with an increase in the adaptation potential. During the predicted 100-year period, the overall elastic–plastic stability of forest formations should increase in the region, especially at the current velocity of global warming. Due to this fact, a significant increase in the ability of boreal and, to a lesser extent, nemoral forests to absorb greenhouse gases should also be expected. Based on the obtained results of regional prediction modeling, coupled study of the adsorption capacity of forest biomes and their adaptation to the changing climate is effective.

Ecological resources of boreal forests in the adsorption of greenhouse gases and in adaptation to global warming

One of the most important ways to achieve the goals stipulated by the Paris (2015) Agreement on Climate Change is to solve a two-fold task: 1) the absorption of CO2 by the forest communities from the atmosphere during global warming and 2) their adaptation to these climate changes, which should ensure the effectiveness of adsorption itself. Given report presents the regional experience of the numerical solution of this task. Calculations of the carbon balance of forest formations in the Oka-Volga River basin were carried out for global forecasts of moderate and extreme warming. The proposed index of labile elastic-plastic stability of forest ecosystems, which characterizes their isomorphic-restorative potential, was used as an indicator of adaptation. For the territory of the Oka river basin using multiple regression methods, a numerical experiment was conducted to assess the effect of the elastic stability of forest formations and the predicted climatic conditions on the carbon balance. A total of 11 linear equations were obtained (with a significance level of P &lt;10-6). In the upcoming 100-year forecast period, the overall elastic-plastic stability of forest formations should increase, and to the greatest extent with extreme warming. Accordingly, one should expect a significant increase in the ability of boreal forests to absorb greenhouse gases. A comparison of the carbon balance values ​​of forest formations obtained with initial (base) and final (final) stability indices gives an unambiguous picture of a significant increase in the adsorption capacity of boreal forests with an increase in their regenerative potential. A decisive contribution to increasing the adsorption of greenhouse gases is made by the growth of reforestation adaptation, which plays the role of a direct environmental factor.