Forest Function Research Articles

Combining satellite and field data reveals Congo's forest types structure, functioning and composition

AbstractTropical moist forests are not the homogeneous green carpet often illustrated in maps or considered by global models. They harbour a complex mixture of forest types organized at different spatial scales that can now be more accurately mapped thanks to remote sensing products and artificial intelligence. In this study, we built a large‐scale vegetation map of the North of Congo and assessed the environmental drivers of the main forest types, their forest structure, their floristic and functional compositions and their faunistic composition. To build the map, we used Sentinel‐2 satellite images and recent deep learning architectures. We tested the effect of topographically determined water availability on vegetation type distribution by linking the map with a water drainage depth proxy (HAND, height above the nearest drainage index). We also described vegetation type structure and composition (floristic, functional and associated fauna) by linking the map with data from large inventories and derived from satellite images. We found that water drainage depth is a major driver of forest type distribution and that the different forest types are characterized by different structure, composition and functions, bringing new insights about their origins and successional dynamics. We discuss not only the crucial role of soil–water depth, but also the importance of consistently reproducing such maps through time to develop an accurate monitoring of tropical forest types and functions, and we provide insights on peculiar forest types (Marantaceae forests and monodominant Gilbertiodendron forests) on which future studies should focus more. Under the current context of global change, expected to trigger major forest structural and compositional changes in the tropics, an appropriate monitoring strategy of the spatio‐temporal dynamics of forest types and their associated floristic and faunistic composition would considerably help anticipate detrimental shifts.

The Responses of Soil Extracellular Enzyme Activities and Microbial Nutrients to the Interaction between Nitrogen and Phosphorus Additions and Apoplastic Litter in Broad-Leaved Korean Pine Forests in Northeast China

The impact of nitrogen and phosphorus deposition alternations, as well as apoplastic litter quality and quantity, on soil nutrient cycling and soil carbon pool processes in forest ecosystems is of considerable importance. Soil ecological enzyme chemistry is a powerful tool for elucidating the nutrient limitations of microbial growth and metabolic processes. In order to explore the responding mechanisms of soil ecological enzyme chemistry to the simultaneous changes in apoplast input and nitrogen and phosphorus deposition in temperate coniferous and broad-leaved mixed forests, an outdoor simulating experiment was conducted. The results demonstrate that the treatments involving apoplastic material and nitrogen and phosphorus additions had significantly impacted soil nutrient levels across different forest types. Apoplastic treatments and N-P additions had a significant effect on the soil total organic carbon (TOC), dissolved organic carbon (DOC), soil total soluble nitrogen (TSN), soil available phosphorus (SAP), soil total nitrogen (TN), soil total phosphorus (TP), and microbial biomass carbon (MBC). However, the effects on soil microbial biomass (MBN) and microbial biomass phosphorus (MBP) were insignificant. The apomictic treatments with N and P addition did not result in a statistically significant change in soil C-hydrolase activities (β-1,4-glucosidase BG, β-1,4-xylosidase BX, cellobiohydrolase CBH, phenol oxidase POX, and peroxidase PER), N-hydrolase activities (β-1,4-N-acetylglucosaminidase NAG and L-leucine aminopeptidase LAP), or P-hydrolase activities (Acid phosphatase AP). Although the apomictic treatments did not yield a significant overall impact on carbon hydrolase activity, they influenced the activity of specific enzymes, such as CBH, LAP, and PER, to varying degrees. The effects on BG, BX, CBH, AP, and C-hydrolase activities were significant for different stand types. The impact of apomictic treatments and N-P additions on soil nitrogen hydrolase activities was inconsequential with a minimal interactive effect. The highest correlation between PER, LAP, and N-hydrolase activities was observed in conjunction with elevated levels of nitrogen and phosphorus addition (N3L0, original litter treatment, and high amounts of N and P addition). These findings may provide a theoretical foundation for the management of ecosystem function in broad-leaved Korean pine forests.

A Bayesian network approach to assess the ecosystem integrity of mangroves in Tampamachoco, Veracruz, Mexico

Given the alarming rates of mangrove forest loss, resource managers must count on information regarding the condition of the mangrove forests. We propose a Bayesian network (BN) to assess mangrove forests' ecosystem integrity (EI) to support a mangrove monitoring system in Mexico. This approach allowed us to infer the system's condition based on variables on forest structure and function. We defined the BN structure based on informal interviews with specialists on vegetation and coastal geomorphology. We applied the expectation-maximization learning algorithm to train the model. Data from plots in two mangrove areas of an Avicennia germinans forest, defined based on their undisturbed and disturbed conditions, were used as training datasets. We applied sensitivity analysis to determine the degree of influence of each model variable. We evaluated the prediction capacity of the BN with a k-fold cross-validation (the process is repeated five times, starting from the database in 2 parts). The variables selected for the model were the Holdridge complexity index (HCI, Holdridge et al., 1971), Leaf area index (LAI), litter production (g/month/m2), leaf C, N and P concentration (%), and leaf N:P ratio. The most critical variable to infer mangrove condition was leaf N:P (Variance reduction = 11%), followed by forest structure variables HCI and LAI (Variance reduction > 5%). The cross-validation to test the model resulted in a minimum square error of 0.3, which indicates a reasonable capacity to predict the condition of mangrove integrity. The BN constructed can diagnose the integrity of a monospecific mangrove forest with acceptable precision, considering the environmental factors that define the forest structure and functioning locally. We then asked the experts to review and modify the model to apply to multispecies mangrove ecosystems and environmental contexts.

Lifting the Profile of Deep Forest Soil Carbon

Forests are the reservoir for a vast amount of terrestrial soil organic carbon (SOC) globally. With increasing soil depth, the age of SOC reportedly increases, implying resistance to change. However, we know little about the processes that underpin deep SOC persistence and what deep SOC is vulnerable to climate change. This review summarizes the current knowledge of deep forest SOC, the processes regulating its cycling, and the impacts of climate change on the fate of deep forest SOC. Our understanding of the processes that influence deep SOC cycling and the extent of SOC stores is limited by available data. Accordingly, there is a large degree of uncertainty surrounding how much deep SOC there is, our understanding of the influencing factors of deep SOC cycling, and how these may be distinct from upper soil layers. To improve our ability to predict deep SOC change, we need to more accurately quantify the deep SOC pool and deepen our knowledge of how factors related to the tree root–soil–microbiome control deep SOC storage and cycling. Thereby, addressing the uncertainty of deep SOC contribution in the global C exchange with climate change and concomitant impacts on forest ecosystem function and resilience.

Tradeoffs between Stand Volume and Understory Vegetation Diversity in Quercus wutaishanica Forests under Climate Change

Natural forests play a crucial role in providing various ecosystem services, including timber production and biodiversity conservation. However, climate change and anthropogenic factors pose a severe threat to competing forest ecosystem services functions. Therefore, to optimize and sustainably utilize competing forest services, tradeoffs are often necessary. This study was conducted in Northwest China to explore tradeoffs aimed at improving the quality of Quercus wutaishanica Mayr natural forests under climate change conditions, focusing on stand volume, timber production, and understory vegetation diversity conservation. Data from 77 field surveys were used to construct a coupled model for stand growth, stand structure, and site conditions. Changes in understory vegetation species number (UVSN) with crown cover were quantified. These models and relationships can be used as tools to estimate tradeoffs. As stand density increased, single-tree volume decreased, whereas timber volume increased. UVSN increased and then decreased with increasing crown cover and was able to maintain a relative maximum at 0.5–0.65. Under the current climatic conditions, the optimum stand densities corresponding to 30, 40, 50, and 60 years were 1390, 1153, 1042, and 871 trees/ha, respectively, to maintain a high UVSN and adequate stand volume. When mean annual temperature rose, stand densities could be reduced to maintain high-quality timber. Although only two major services were considered, the tradeoffs presented in this study can inform future research to improve the quality of natural forests.

Community structure, diversity and function of endophytic and soil microorganisms in boreal forest.

Despite extensive studies on soil microbial community structure and functions, the significance of plant-associated microorganisms, especially endophytes, has been overlooked. To comprehensively anticipate future changes in forest ecosystem function under future climate change scenarios, it is imperative to gain a thorough understanding of the community structure, diversity, and function of both plant-associated microorganisms and soil microorganisms. In our study, we aimed to elucidate the structure, diversity, and function of leaf endophytes, root endophytes, rhizosphere, and soil microbial communities in boreal forest. The microbial structure and composition were determined by high-throughput sequencing. FAPROTAX and FUNGuild were used to analyze the microbial functional groups. Our findings revealed significant differences in the community structure and diversity of fungi and bacteria across leaves, roots, rhizosphere, and soil. Notably, we observed that the endophytic fungal or bacterial communities associated with plants comprised many species distinct from those found in the soil microbial communities, challenging the assumption that most of endophytic fungal or bacterial species in plants originate from the soil. Furthermore, our results indicated noteworthy differences in the composition functional groups of bacteria or fungi in leaf endophytes, root endophytes, rhizosphere, and soil, suggesting distinct roles played by microbial communities in plants and soil. These findings underscore the importance of recognizing the diverse functions performed by microbial communities in both plant and soil environments. In conclusion, our study emphasizes the necessity of a comprehensive understanding of the structure and function microbial communities in both plants and soil for assessing the functions of boreal forest ecosystems.

Boreal tree species diversity increases with global warming but is reversed by extremes.

Tree species diversity is essential to sustaining stable forest ecosystem functioning. However, it remains unclear how boreal tree species diversity has changed in response to climate change and how it is associated with productivity and the temporal stability of boreal forest ecosystems. By combining 5,312 field observations and 55,560 Landsat images, here we develop a framework to estimate boreal tree species diversity (represented by the Shannon diversity index, H') for the years 2000, 2010 and 2020. We document an average increase in H' by 12% from 2000 to 2020 across the boreal forests. This increase accounts for 53% of all boreal forest areas and mainly occurs in the eastern forest-boreal transition region, the Okhotsk-Manchurian taiga and the Scandinavian-Russian taiga. Tree species diversity responds positively to increasing temperatures, but the relationship is weakened for higher temperature changes, and in areas of extreme warming (>0.065 °C yr-1), a negative impact on tree species diversity is found. We further show that the observed spatiotemporal increase in diversity is significantly associated with increased productivity and temporal stability of boreal forest biomass. Our results highlight climate-warming-driven increases in boreal tree species diversity that positively affect boreal ecosystem functioning but are countered in areas of extreme warming.

Effects of Climate, Soil, Topography and Disturbance on Liana Prevalence.

Lianas (woody vines and climbing monocots) are increasing in abundance in many tropical forests with uncertain consequences for forest functioning and recovery following disturbances. At a global scale, these increases are likely driven by disturbances and climate change. Yet, our understanding of the environmental variables that drive liana prevalence at regional scales is incomplete and geographically biased towards Latin America. To address this gap, we present a comprehensive study evaluating the combined effects of climate, soil, disturbance and topography on liana prevalence in the Australian Wet Tropics. We established 31 20 × 20 m vegetation plots along an elevation gradient in low disturbance (canopy closure ≥ 75%) and high disturbance (canopy closure ≤ 25%) forest stands. In these plots, all tree and liana (defined as all woody dicot vines and climbing monocots, i.e., rattans) stems ≥ 1 cm DBH were measured and environmental data were collected on climate, soil and topography. Generalised linear models were used with multi-model averaging to quantify the relative effects of the environmental variables on measures of liana prevalence (liana-tree basal area ratio, woody vine basal area and stem density and rattan stem density). Liana prevalence decreased with elevation but increased with disturbance and mean annual precipitation. The increase in the liana-tree ratio with precipitation was more pronounced for highly disturbed sites. Like other tropical regions, disturbance is an important driver of liana prevalence in Australian rainforests and appears to interact with climate to increase liana-tree ratios. The observed increase in liana-tree ratio with precipitation contrasts findings from elsewhere but is confounded by correlated changes in elevation and temperature, which highlights the importance of regional studies. Our findings show that forests with high disturbance and climatic conditions favourable to lianas are where lianas most likely to outcompete trees and impede forest recovery.

Well-Being and Sustainable Utilization of Forest Environment with Diverse Vegetation Distributions

Forest landscape space is the basic unit of forest landscape resources. Healthy forest landscape resources can not only improve the sustainable cycle of forest ecological service function, but also have a positive impact on human health and well-being. Evidence supports the view that the forest environment is beneficial to people’s health, and further discussion of the dose response between environmental attributes and physical and mental recovery has been widely carried out by scholars. As an important component of environmental attributes, it is necessary to clarify the relationship between vegetation distribution and users’ health in order to better plan, design, and utilize forest environmental resources. This study mainly used the virtual immersive forest environment video in VR, and used the difference test in SPSS 23.0 to clarify whether the distribution of vegetation in the forest environment will affect the physiological and psychological recovery effect of users. The main results are as follows: (1) Experiencing the forest environment can promote users’ physiological and psychological health, and its recovery effect is significantly better than the indoor environment (p < 0.05). (2) The distribution of vegetation in the forest environment will affect users’ physiological and psychological recovery effect. Among them, in the cluster and randomly distributed forest environments, the relaxation and concentration of users can be improved mainly by alleviating their negative emotions. In the evenly distributed forest environment, users mainly achieve the purpose of relaxation by improving their vitality and positive emotions. These results show that the distribution of vegetation is one of the factors for the restoration of forest environment. In the future design and management of the forest environment, the health and well-being of users can be effectively enhanced by getting involved with the vegetation distribution in the site, aiming to provide a scientific basis for the promotion of the rehabilitation function of forest landscape space and its sustainable utilization, thus promoting the sustainable development of forest resources and improving people’s quality of life.

Optimizing afforestation and reforestation strategies to enhance ecosystem services in critically degraded regions

Human activity has caused massive forest ecosystem damage, threatening the global environmental balance. Afforestation and reforestation are crucial strategies for the restoration of forest ecosystem functions. This study was conducted on Belitung Island, Indonesia, which has experienced forest degradation due to mining activity and is currently undergoing forest restoration efforts. This study aimed to identify priority areas for afforestation and reforestation using an innovative approach that integrates multi-criteria analysis (MCA) and machine-learning techniques based on ecosystem service (ES) indicators, wildfire susceptibility, and environmental pressure. This study is the first to combine long-term remote sensing data with machine learning to develop priority scenarios for afforestation and reforestation. Results show that low-priority afforestation areas cover 24,479.66 ha (20.45 %), medium-priority areas 58,703.30 ha (49.04 %), and high-priority areas 36,521.98 ha (30.51 %). For reforestation, low-priority areas cover 23,123.45 ha (30.45 %), medium-priority areas 38,197.36 ha (50.3 %), and high-priority areas 14,618.27 ha (19.25 %). This study is expected to serve as a reference for sustainable forest ecosystem restoration efforts in various regions by leveraging ES approaches and environmental conditions using remote-sensing technology.

Timber Harvest Planning Using Reinforcement Learning: A Feasibility Study

This study developed a forest management plan model using reinforcement learning (Q-learning) to optimize both the economic and ecological functions of forests. Management objectives for national forests were established, and forest conditions were analyzed using GIS spatial data and administrative records. A 60-year forest management plan was formulated to predict timber production and management performance across different regions and time periods. Our analysis revealed that Scenario 3 (Carbon Storage Priority) demonstrated the highest economic value, starting at approximately KRW 576.2 billion in the initial period and escalating to KRW 775.7 billion over six 10-year periods, totaling 60 years. In addition to its economic performance, Scenario 3 effectively improved forest age class structure and ensured a stable timber supply, making it the most balanced approach for sustainable forest management. By focusing on carbon storage as a key management goal, this approach highlights the potential for achieving both economic and environmental benefits concurrently. These results suggest that reinforcement learning is a powerful tool for developing long-term forest management strategies that address multiple objectives, including economic viability, ecological sustainability, and resource optimization.

Farmers’ Perception of Shelter Forests and the Influencing Factors in Windy Desert Areas of the Hexi Corridor, China

Shelter forest systems in the sandy areas mainly comprise farmland shelter forests (FSF) and windbreak and sand-fixing forests (WSF). Through a questionnaire survey of farmers in the oasis–desert transition zone of the windy desert areas of the Hexi Corridor in China, a perception assessment model of farmers’ perception of the status quo and ecosystem service function of shelter forests was constructed, and the willingness of farmers to pay for shelter forest construction and protection was measured. Influencing factors for the farmers’ perception of shelter forests were analyzed by a multiple regression analysis. The results showed problems with pests and diseases all present in FSF and WSF, the destruction of farmland in FSF, and water scarcity in WSF. Farmers evaluated the ecological role of shelter forests as the most obvious in windbreak and sand fixation; intermediate in the four ecological roles of leisure and recreation, agricultural production, a sense of locality, and climate regulation; and the smallest in soil improvement. Nearly 95% of farmers are willing to donate funds to shelter forest construction and protection, and the average amount the farmers were willing to pay was CNY 54.30 per year. Willingness to pay, annual household income, gender, environmental experience, age, and interview area have significant effects on farmers’ perception of shelter forests. Finally, in this paper, we recommend increasing motivation through government financial support and training for farmers to address pests and diseases, water security, and the destruction of farmland in shelter forests to ensure healthy and sustainable growth.

The White-backed Woodpecker (Dendrocopos leucotos) as an umbrella species for threatened saproxylic beetle communities in Central European beech forests

The umbrella species concept is a popular conservation planning tool which postulates that conservation schemes targeting a specific species will indirectly benefit many other sympatric species. In Scandinavia and Central Europe, the White-backed Woodpecker (Dendrocopos leucotos) is considered an umbrella species for woodland birds and cryptogam species of conservation concern. Whether this also applies to saproxylic beetles, a group of high conservation concern, remains open. Therefore, we tested that umbrella function in Central European beech forests that are currently recolonized by this woodpecker. Relying on radiotracking data, we compared saproxylic beetle communities within the breeding home ranges of White-backed Woodpeckers (high and low activity of the bird) against forests with ascertained absence of the bird (control). Bayesian inference for linear regressions identified that species richness of threatened saproxylic beetles was 1.51 (lower and upper 5 % PPCrI=[1.09; 2.01]) times higher in sites with high White-backed Woodpecker activity compared to the control. Community composition analyses on threatened saproxylic beetles showed a reduced β-diversity at low and high White-backed Woodpecker sites compared to the control. Finally, an indicator species analysis showed that 17 saproxylic beetle species, including 4 threatened species, were positively associated with White-backed Woodpecker’s breeding home ranges, while only 3 species, but no threatened species, were associated with the control sites. Overall, our results suggest that the White-backed Woodpecker plays the role of an umbrella species for threatened saproxylic beetle communities, opening new opportunities for conservation planning in European beech forests.

Differential spatial responses and assembly mechanisms of soil microbial communities across region-scale Taiga ecosystems

Different soil microbial communities play distinct key roles in regulating forest ecosystem processes and functions. However, the differences in spatial variability and assembly mechanisms of various taiga forest soil microbial taxa remain poorly understood. Here, we assessed the spatial patterns of bacterial and fungal communities, their assembly processes, and the influencing factors in taiga forest ecosystems in Xinjiang, China. A significant distance decay pattern was observed in the similarity of bacterial and fungal communities, with bacterial communities exhibiting a more pronounced pattern than fungal communities. Stochastic and deterministic processes governed together to drive soil bacterial community assembly, whereas stochastic processes dominated fungal community assembly. The coexistence networks revealed that the interactions of bacterial and fungal networks in the four regions are primarily based on interspecies symbiosis, with fungal coexistence networks demonstrating greater stability than bacterial networks. Additionally, the study identified a positive relationship between the modularity of bacterial networks and dispersal limitation. Analysis of environmental factors revealed that soil pH primarily affects the characteristics and assembly mechanisms of bacterial communities, while vegetation conditions primarily affect fungal diversity and composition, with other unconsidered environmental variables influencing the fungal community assembly process. This study emphasized the distinct ways in which bacteria and fungi respond to environmental factors and interspecies interactions. Our results suggested that distinct restoration measures should be implemented for bacteria and fungi in future conservation efforts for forest soil microorganisms.

First measurement of the Mg ii forest correlation function in the Epoch of Reionization

Abstract Strong low-ionization transitions like the Mg ii λ2796, 2804Å doublet are believed to produce a detectable ‘metal-line forest’, if metals pollute the neutral IGM. We measure the auto-correlation of the Mg II forest transmission using ten ground based z ≥ 6.80 quasar spectra probing the redshift range $5.96 < z_{\rm Mg\, {\small II}} < 7.42$ ($z_{\rm Mg\, {\small II}, median} = 6.47$). The correlation function exhibits strong small-scale clustering and a pronounced peak at the doublet velocity (Δv = 768 km s−1) arising from discrete absorbers in the CGM of galaxies. After these strong absorbers are identified and masked the signal is consistent with noise. Our measurements are compared to a suite of models generated by combining a large hydrodynamical simulation with a semi-numerical reionization topology, assuming a simple uniform enrichment model. We obtain a 95% credibility upper limit of [Mg/H] < −3.73 at $z_{\rm Mg\, {\small II},median} = 6.47$, assuming uninformative priors on [Mg/H] and the IGM neutral fraction $x_{\rm {H\, {\small I}}}$. Splitting the data into low-z ($5.96 < z_{\rm Mg\, {\small II}} < 6.47$; $z_{\rm Mg\, {\small II},median} = 6.235$) and high-z ($6.47 < z_{\rm Mg\, {\small II}} < 7.42$; $z_{\rm Mg\, {\small II},median} = 6.72$) subsamples again yields null-detections and 95% upper limits of [Mg/H] < −3.75 and [Mg/H] < −3.45, respectively. These first measurements set the stage for making the Mg II forest an emerging tool to precisely constrain the Universe reionization and enrichment history.

Tree species diversity impacts on ecosystem services of temperate forests

Tree species diversity is crucial for forest ecosystem services as it relates to ecosystem functions. However, it remains unclear how spatially continuous tree species diversity affects multiple ecosystem services in temperate forests that undergo various management practices. We mapped the spatial pattern of tree species diversity represented by the Shannon diversity index, H’ in the temperate forests of Northeast China using 1,028 in situ observations and 846 Sentinel-2 images. We further analysed the relationships between tree species diversity and ecosystem services including carbon storage, water yield, and soil retention, while controlling for the covarying effects of multiple forest attributes including tree height, leaf area index (LAI), and stand age. Our results showed distinct spatial variations in tree species diversity across different forest management practices, with natural forests exhibiting a higher diversity compared to managed natural forests and planted forests. Tree species diversity was found to be positively associated with improved ecosystem services, particularly water yield and soil retention, while the effects plateaued above diversity of 1.0 (Shannon index values). We also showed that LAI was the most important factor influencing carbon storage, while tree species diversity and stand age were crucial for water yield and soil retention. These results highlight the importance of maintaining diverse tree species to improve ecosystem services in temperate forests, providing a robust framework for effectively monitoring and managing forest ecosystems with regards to sustainable forest functioning.

Budworms, beetles and wildfire: Disturbance interactions influence the likelihood of insect‐caused disturbances at a subcontinental scale

Abstract Irruptive forest insects are a leading biotic disturbance across temperate and boreal forests. Outbreaks of forest insects are becoming more frequent and extensive due to anthropogenic drivers (e.g. climate and land‐use), perhaps increasing the likelihood that forests will experience multiple insect‐caused disturbances. Across the fire‐prone Douglas‐fir forests of western North America, recent outbreaks of the western spruce budworm and Douglas‐fir beetle have impacted large expanses of forests, with a higher degree of overlap than expected in some ecoregions. Outbreaks of both insects are positively related to host availability and exhibit density‐dependent population dynamics that are affected by climate and weather. Here, we leverage data from aerial detection surveys, estimates of host availability, climate and weather, and categorized fire severity to describe the spatial overlap between western spruce budworm and Douglas‐fir beetle and assess: (1) how climate and host availability influence the biogeography of outbreaks; (2) how weather incites outbreaks; and finally, (3) how prior disturbances (fire and biotic) affect the subsequent outbreak likelihood of western spruce budworm and Douglas‐fir beetle. Models demonstrate that western spruce budworm and Douglas‐fir beetle share similar predisposing drivers of outbreaks. Outbreaks of both insects were more likely to occur following warm weather, but only beetle outbreaks were more likely following drought. When controlling for differences in outbreak distribution and inciting factors, results indicate that both prior fire and interspecific disturbance altered the likelihood of subsequent insect‐caused disturbance. Specifically, Douglas‐fir beetle outbreaks were more likely to occur for several years following low severity fire, but less likely otherwise. Prior defoliation, especially longer duration defoliation, increased the likelihood of beetle outbreak within stands and across the landscape. On the contrary, western spruce budworm outbreaks were less likely to occur following fire, while prior beetle activity dampened budworm outbreak likelihood for several years, and then eventually increased outbreak likelihood. Synthesis: Biotic–biotic disturbance interactions have the potential to amplify the incidence of insect‐caused disturbance across subcontinental scales. Our findings highlight the need for future work on mechanistic linkages between biotic disturbance agents as well as the ramifications for forest trajectories and function.

Principle, structure and application progress of the forest landscape model FireBGCv2.

Forest landscape model can quantitatively simulate the spatiotemporal variations in forest structure and function at the landscape scale based on traditional field survey data and mathematical models, providing a reference for the formulation of scientific forest management strategies. FireBGCv2 is one of the representative models currently used in the research area of forest landscape changes. It can simulate ecological processes at various scales, including trees scale (tree growth, establishment, and mortality), stand scale (carbon and nitrogen pools, fuel treatment, decomposition), site scale (resource competition and species phenology), and landscape scale (seed dispersal and wildfire disturbances), and the effects of those processes on forest landscape structure and function. The advantage of this model lies in its ability to simulate multiple ecological processes while considering the diversity and complexity of ecosystems. However, it also has drawbacks, such as high computational demands and complexity of use. We summarized the basic principles and structure of FireBGCv2 and introduced its application progress in forest landscape research and management. Currently, the application of the FireBGCv2 model, both domestically and internationally, mainly focused on exploring the interactions between fire, climate, and vegetation, quantifying the spatial and temporal dynamics of fires, and describing potential fire dynamics under future climate scenarios and land management strategies. With the in-depth development of forest landscape model theories and applications, the future prospects of FireBGCv2 include improving and updating the model's algorithms, adding new functional modules to explore fire management issues, and meeting the needs of different users.

Natural forest colonisation as a management strategy to restore soil functioning of abandoned agricultural lands

Abstract Land abandonment promotes forest expansion into abandoned agricultural lands in Europe. This process leads to changes that affect several ecosystem services, but it is considered a low‐cost strategy to restore soil functions in past agricultural lands. Soil microbial communities play a key role in restoring functions. However, the relationship among forest expansion, microbial communities, and soil functioning is unclear. In this study, we used a Juniperus thurifera expansion gradient on abandoned agricultural lands in Alto Tajo National Park (Spain) to discover the changes elicited by the soil microbial communities and their functions along this gradient considering two microhabitats, under the canopy and open areas. Specifically, our objectives were (i) to analyse how soil properties (organic matter and pH), microbial communities (using PLFAs‐NFLAs) and enzymatic activities (related to C, N and P cycling) varied along the forest expansion gradient and between microhabitats and (ii) to decipher the pathways by which soil properties control the carbon and nutrient cycling in soils. The forest expansion gradient had a direct negative effect on phosphatase activity. The microhabitat showed a positive direct effect on organic matter content, pH, actinomycetes and arbuscular mycorrhizal fungi biomass and on soil C and P cycling. Moreover, the biomass of gram‐positive bacteria determined the biomass of other microbial groups. Synthesis and Applications: Though its effectiveness is variable, passive restoration can be more effective than active restoration. Our research indicates that passive tree colonisation of past agricultural land is enough to achieve soil functionality similar to a mature forest for most variables studied. However, some variables would need more time to reach mature forest levels, such as total microbial biomass and organic matter content. Therefore, to support ecosystem recovery, the management of this applied forest ecology strategy requires continuous monitoring of newly established trees and soil to elucidate the time needed to achieve mature soil properties.

The Combined Effects of the Thermal Environment and Air Quality at Recreation Places on the Physiology and Psychology of People in Urban Parks

Urban forests, crucial to urban ecosystems, are increasingly threatened by the challenges of urbanization, such as deteriorating thermal environments and declining air quality. Despite their recognized benefits to city dwellers’ quality of life, a systematic understanding of the impact of these environmental factors on public psychophysiological well-being in recreational sites is a notable gap in the literature. The objective of this research was to bridge this gap by examining the effects of the thermal environment and air quality in urban forests on the public’s perception, offering scientific evidence to inform environmental optimization and health management strategies for urban parks, essential for sustainable urban development and public health. Three urban parks in Fuzhou, Fujian Province, namely Fuzhou National Forest Park, Xihu Park, and Jinniushan Sports Park, were selected as research sites. Environmental monitoring and questionnaire surveys were conducted at 24 recreation places from October to December 2020, collecting temperature, humidity, and wind speed; the atmospheric composition includes PM2.5, PM10, negative oxygen ion, and psychophysiological data from the public. Multivariate statistical methods were employed to assess the environmental characteristics of different recreation places types and their impact on public health. The findings reveal that environmental factors explained 1.9% to 11.8% of the variation in physiological and psychological responses, mainly influenced by temperature, wind speed, and negative oxygen ions. Forests and waterfront recreation places significantly outperform canopy and open recreation places in promoting mental invigoration, stress relief, emotional tranquility, and attention restoration. Environmental monitoring results indicate that favorable meteorological conditions and good air quality are crucial for enhancing the service functions of recreation places. Notably, the positive correlation between a negative air ion concentration and psychological well-being provides a novel perspective on understanding the health benefits of urban forests. The thermal environment and air quality of urban recreation places exert a significant influence on the psychophysiological status of the public. Increasing green coverage, improving water body environments, and rationally planning recreation places layout are of great theoretical and practical significance for enhancing the environmental quality and service functions of urban forests.