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Future climate presents conflicting implications for forest biomass. We evaluate how plant hydraulic traits, elevated CO2 levels, warming, and changes in precipitation affect forest primary productivity, evapotranspiration, and the risk of hydraulic failure. We used a dynamic vegetation model with plant hydrodynamics (FATES-HYDRO) to simulate the stand-level responses to future climate changes in a wet tropical forest in Barro Colorado Island, Panama. We calibrated the model by selecting plant trait assemblages that performed well against observations. These assemblages were run with temperature and precipitation changes for two greenhouse gas emission scenarios (2086-2100: SSP2-45, SSP5-85) and two CO2 levels (contemporary, anticipated). The risk of hydraulic failure is projected to increase from a contemporary rate of 5.7% to 10.1-11.3% under future climate scenarios, and, crucially, elevated CO2 provided only slight amelioration. By contrast, elevated CO2 mitigated GPP reductions. We attribute a greater variation in hydraulic failure risk to trait assemblages than to either CO2 or climate. Our results project forests with both faster growth (through productivity increases) and higher mortality rates (through increasing rates of hydraulic failure) in the neo-tropics accompanied by certain trait plant assemblages becoming nonviable.

Tree growth and longevity trade-offs fundamentally shape the terrestrial carbon balance. Yet, we lack a unified understanding of how such trade-offs vary across the world's forests. By mapping life history traits for a wide range of species across the Americas, we reveal considerable variation in life expectancies from 10 centimeters in diameter (ranging from 1.3 to 3195 years) and show that the pace of life for trees can be accurately classified into four demographic functional types. We found emergent patterns in the strength of trade-offs between growth and longevity across a temperature gradient. Furthermore, we show that the diversity of life history traits varies predictably across forest biomes, giving rise to a positive relationship between trait diversity and productivity. Our pan-latitudinal assessment provides new insights into the demographic mechanisms that govern the carbon turnover rate across forest biomes.

While there has been significant progress in controlling falciparum malaria in the Lao Peoples Democratic Republic (PDR), sporadic cases persist in southern provinces where the extent and patterns of transmission remain largely unknown. To assess parasite transmission in this area, 53 Plasmodium falciparum (Pf) positive cases detected through active test and treat campaigns from December 2017 to November 2018 were sequenced, targeting 204 highly polymorphic amplicons. Two R packages, MOIRE and Dcifer, were applied to assess the multiplicity of infections (MOI), effective MOI (eMOI), within-host parasite relatedness, and between-host parasite relatedness ([Formula: see text]). Genomic data were integrated with survey data to characterize the temporal and spatial structures of identified clusters. The positive cases were mainly captured during the focal test and treat campaign conducted in 2018, and in the Pathoomphone area, which had the highest test positivity and forest activity. About 30% of the cases were polyclonal infections, with over half of theses (63%) showing within-host relatedness greater than 0.6, suggesting that cotransmission rather than superinfection was primarily responsible for maintaining polyclonality. A large majority of cases (81%) were infected by parasites genetically linked to one or more other cases. We identified five genetically distinct clusters in forest fringe villages within the Pathoomphone district, characterized by a high degree of genetic relatedness between parasites (mean [Formula: see text] = 0.8). Four smaller clusters of 2-3 cases linked Moonlapamok and Pathoomphone districts, with an average [Formula: see text] of 0.6, suggesting cross-district transmission. Most of the clustered cases occurred within 20 km and 2 months of each other, consistent with focal transmission. Transmission clusters identified in this study confirm the role of ongoing focal parasite transmission occurring within the forest or forest-fringe in the highly mobile population.

The fundamental trade-off between current and future reproduction has long been considered to result in a tendency for species that can grow large to begin reproduction at a larger size. Due to the prolonged time required to reach maturity, estimates of tree maturation size remain very rare and we lack a global view on the generality and the shape of this trade-off. Using seed production from five continents, we estimate tree maturation sizes for 486 tree species spanning tropical to boreal climates. Results show that a species' maturation size increases with maximum size, but in a non-proportional way: the largest species begin reproduction at smaller sizes than would be expected if maturation were simply proportional to maximum size. Furthermore, the decrease in relative maturation size is steepest in cold climates. These findings on maturation size drivers are key to accurately represent forests' responses to disturbance and climate change.

Present and future climatic trends are expected to markedly alter water fluxes and stores in the hydrologic cycle. In addition, water demand continues to grow due to increased human use and a growing population. Sustainably managing water resources requires a thorough understanding of water storage and flow in natural, agricultural, and urban ecosystems. Measurements of stable isotopes of water (hydrogen and oxygen) in the water cycle (atmosphere, soils, plants, surface water, and groundwater) can provide information on the transport pathways, sourcing, dynamics, ages, and storage pools of water that is difficult to obtain with other techniques. However, the potential of these techniques for practical questions has not been fully exploited yet. Here, we outline the benefits and limitations of potential applications of stable isotope methods useful to water managers, farmers, and other stakeholders. We also describe several case studies demonstrating how stable isotopes of water can support water management decision-making. Finally, we propose a workflow that guides users through a sequence of decisions required to apply stable isotope methods to examples of water management issues. We call for ongoing dialogue and a stronger connection between water management stakeholders and water stable isotope practitioners to identify the most pressing issues and develop best-practice guidelines to apply these techniques.

Spatiotemporal patterns of plant water uptake, loss, and storage exert a first-order control on photosynthesis and evapotranspiration. Many studies of plant responses to water stress have focused on differences between species because of their different stomatal closure, xylem conductance, and root traits. However, several other ecohydrological factors are also relevant, including soil hydraulics, topographically driven redistribution of water, plant adaptation to local climatic variations, and changes in vegetation density. Here, we seek to understand the relative importance of the dominant species for regional-scale variations in woody plant responses to water stress. We map plant water sensitivity (PWS) based on the response of remotely sensed live fuel moisture content to variations in hydrometeorology using an auto-regressive model. Live fuel moisture content dynamics are informative of PWS because they directly reflect vegetation water content and therefore patterns of plant water uptake and evapotranspiration. The PWS is studied using 21,455 wooded locations containing U.S. Forest Service Forest Inventory and Analysis plots across the western United States, where species cover is known and where a single species is locally dominant. Using a species-specific mean PWS value explains 23% of observed PWS variability. By contrast, a random forest driven by mean vegetation density, mean climate, soil properties, and topographic descriptors explains 43% of observed PWS variability. Thus, the dominant species explains only 53% (23% compared to 43%) of explainable variations in PWS. Mean climate and mean NDVI also exert significant influence on PWS. Our results suggest that studies of differences between species should explicitly consider the environments (climate, soil, topography) in which observations for each species are made, and whether those environments are representative of the entire species range.

Net nitrogen mineralization (Nmin) and nitrification regulate soil N availability and loss after severe wildfires in boreal forests experiencing slow vegetation recovery. Yet, how microorganisms respond to postfire phosphorus (P) enrichment to alter soil N transformations remains unclear in N-limited boreal forests. Here, we investigated postfire N-P interactions using an intensive regional-scale sampling of 17 boreal forests in the Greater Khingan Mountains (Inner Mongolia-China), a laboratory P-addition incubation, and a continental-scale meta-analysis. We found that postfire soils had an increased risk of N loss by accelerated Nmin and nitrification along with low plant N demand, especially during the early vegetation recovery period. The postfire N/P imbalance created by P enrichment acts as a "N retention" strategy by inhibiting Nmin but not nitrification in boreal forests. This strategy is attributed to enhanced microbial N-use efficiency and N immobilization. Importantly, our meta-analysis found that there was a greater risk of N loss in boreal forest soils after fires than in other climatic zones, which was consistent with our results from the 17 soils in the Greater Khingan Mountains. These findings demonstrate that postfire N-P interactions play an essential role in mitigating N limitation and maintaining nutrient balance in boreal forests.

We conducted a research campaign in a neotropical rainforest in Costa Rica throughout the drought phase of an El-Nino Southern Oscillation event to determine microbial community dynamics and soil C fluxes. Our study included nests of the leafcutter ant Atta cephalotes, as soil disturbances made by these ecosystem engineers may influence microbial drought response. Drought decreased the diversity of microbes and the abundance of core microbiome taxa, including Verrucomicrobial bacteria and Sordariomycete fungi. Despite initial responses of decreasing diversity and altered composition, 6 months post-drought the microbiomes were similar to pre-drought conditions, demonstrating the resilience of soil microbial communities to drought events. A. cephalotes nests altered fungal composition in the surrounding soil, and reduced both fungal mortality and growth of Acidobacteria post-drought. Drought increased CH4 consumption in soils due to lower soil moisture, and A. cephalotes nests decrease the variability of CH4 emissions in some soil types. CH4 emissions were tracked by the abundance of methanotrophic bacteria and fungal composition. These results characterize the microbiome of tropical soils across both time and space during drought and provide evidence for the importance of leafcutter ant nests in shaping soil microbiomes and enhancing microbial resilience during climatic perturbations.

Wildfires are increasing in duration and intensity across the United States' Pacific West region, resulting in heightened particulate matter from smoke in the atmosphere. Levels of peak particulate matter are concurrent to peak visitor attendance at National Parks, given seasonal alignment with summer vacation travel and heightened forest fire conditions. Particulate matter threatens visitor health and safety and contributes to poor visibility and a deteriorated visitor experience. To assess visitation response to diminished air quality, we utilized wildfire-generated particulate matter (PM2.5) data in conjunction with monthly attendance records for three ecoregions containing eight national parks in Washington, Oregon, and California from 2009 to 2019. We analyzed daily PM2.5 levels from data gridded at the 10 km scale for National Park Service units by Level III forest ecoregions within the National Park Service's Pacific West Unit. Data were then compared to normalized monthly visitation trends for each of the ecoregions using two statistical methods Kendall's Tau and Analysis of Variance (ANOVA) with post-hoc Tukey tests. Results demonstrate that attendance at these national parks does not decrease in response to increased PM2.5 levels. Instead, we see several statistically significant increases in attendance across these ecoregions during periods of reduced air quality. Of 115 shifts between air quality categories during the busy season of July to September, there are no significant decreases in attendance as air quality worsens. These findings suggest that visitors are willing to tolerate reduced air quality compared to other factors such as temperature or precipitation. Given that park units within each ecoregion feature diverse historical contexts, varied built environments, and unique ecological systems, our discussion specifically addresses managerial concerns associated with maintained high levels of visitation during suboptimal, and potentially dangerous, conditions. There is substantial need for specific, scalable approaches to mitigate adverse health and experiential impacts as visitors are exposed to increased risks during a range of exertional activities associated with diverse settings.

Soil fungi belonging to different functional guilds, such as saprotrophs, pathogens, and mycorrhizal symbionts, play key roles in forest ecosystems. To date, no study has compared the actual gene expression of these guilds in different forest soils. We used metatranscriptomics to study the competition for organic resources by these fungal groups in boreal, temperate, and Mediterranean forest soils. Using a dedicated mRNA annotation pipeline combined with the JGI MycoCosm database, we compared the transcripts of these three fungal guilds, targeting enzymes involved in C- and N mobilization from plant and microbial cell walls. Genes encoding enzymes involved in the degradation of plant cell walls were expressed at a higher level in saprotrophic fungi than in ectomycorrhizal and pathogenic fungi. However, ectomycorrhizal and saprotrophic fungi showed similarly high expression levels of genes encoding enzymes involved in fungal cell wall degradation. Transcripts for N-related transporters were more highly expressed in ectomycorrhizal fungi than in other groups. We showed that ectomycorrhizal and saprotrophic fungi compete for N in soil organic matter, suggesting that their interactions could decelerate C cycling. Metatranscriptomics provides a unique tool to test controversial ecological hypotheses and to better understand the underlying ecological processes involved in soil functioning and carbon stabilization.

BACKGROUND AND AIMS: The increased likelihood and severity of storm events has brought into focus the role of coastal ecosystems in provision of shoreline protection by attenuating wave energy. Canopy-forming kelps, including giant kelp (Macrocystis pyrifera), are thought to provide this ecosystem service, but supporting data are extremely limited. Previous in situ examinations relied mostly on comparisons between nominally similar sites with and without kelp. Given that other factors (especially seafloor bathymetry and topographic features) often differ across sites, efforts to isolate the effects of kelp on wave energy propagation confront challenges. In particular, it can be difficult to distinguish wave energy dissipation attributable to kelp from frictional processes at the seabed that often covary with the presence of kelp. Here, we use an ecological transition from no kelp to a full forest, at a single site with static bathymetry, to resolve unambiguously the capacity of giant kelp to damp waves. METHODS: We measured waves within and outside rocky reef habitat, in both the absence and the presence of giant kelp, at Marguerite Reef, Palos Verdes, CA, USA. Nested within a broader kelp restoration project, this site transitioned from a bare state to one supporting a fully formed forest (density of 8 stipes m-2). We quantified, as a function of incident wave conditions, the decline in wave energy flux attributable to the presence of kelp, as waves propagated from outside and into reef habitat. KEY RESULTS: The kelp forest damped wave energy detectably, but to a modest extent. Interactions with the seabed alone reduced wave energy flux, on average, by 12 ± 1.4 % over 180 m of travel. The kelp forest induced an additional 7 ± 1.2 % decrease. Kelp-associated declines in wave energy flux were slightly greater for waves of longer periods and smaller wave heights. CONCLUSIONS: Macrocystis pyrifera forests have a limited, albeit measurable, capacity to enhance shoreline protection from nearshore waves. Expectations that giant kelp forests, whether extant or enhanced through restoration, have substantial impacts on wave-induced coastal erosion might require re-evaluation.

Numerous studies have shown reduced performance in plants that are surrounded by neighbours of the same species1,2, a phenomenon known as conspecific negative density dependence (CNDD)3. A long-held ecological hypothesis posits that CNDD is more pronounced in tropical than in temperate forests4,5, which increases community stabilization, species coexistence and the diversity of local tree species6,7. Previous analyses supporting such a latitudinal gradient in CNDD8,9 have suffered from methodological limitations related to the use of static data10-12. Here we present a comprehensive assessment of latitudinal CNDD patterns using dynamic mortality data to estimate species-site-specific CNDD across 23 sites. Averaged across species, we found that stabilizing CNDD was present at all except one site, but that average stabilizing CNDD was not stronger toward the tropics. However, in tropical tree communities, rare and intermediate abundant species experienced stronger stabilizing CNDD than did common species. This pattern was absent in temperate forests, which suggests that CNDD influences species abundances more strongly in tropical forests than it does in temperate ones13. We also found that interspecific variation in CNDD, which might attenuate its stabilizing effect on species diversity14,15, was high but not significantly different across latitudes. Although the consequences of these patterns for latitudinal diversity gradients are difficult to evaluate, we speculate that a more effective regulation of population abundances could translate into greater stabilization of tropical tree communities and thus contribute to the high local diversity of tropical forests.

Ecological communities can be stable over multiple generations, or rapidly shift into structurally and functionally different configurations. In kelp forest ecosystems, overgrazing by sea urchins can abruptly shift forests into alternative states that are void of macroalgae and primarily dominated by actively grazing sea urchins. Beginning in 2014, a sea urchin outbreak along the central coast of California resulted in a patchy mosaic of remnant forests interspersed with sea urchin barrens. In this study, we used a 14-year subtidal monitoring dataset of invertebrates, algae, and fishes to explore changes in community structure associated with the loss of forests. We found that the spatial mosaic of barrens and forests resulted in a region-wide shift in community structure. However, the magnitude of kelp forest loss and taxonomic-level consequences were spatially heterogeneous. Taxonomic diversity declined across the region, but there were no declines in richness for any group, suggesting compositional redistribution. Baseline ecological and environmental conditions, and sea urchin behaviour, explained the persistence of forests through multiple stressors. These results indicate that spatial heterogeneity in preexisting ecological and environmental conditions can explain patterns of community change.

Tropical rainforests of Latin America (LATAM) are one of the world's largest carbon sinks, with substantial future carbon sequestration potential and contributing a major proportion of the global supply of forest carbon credits. LATAM is poised to contribute predominantly towards high-quality forest carbon offset projects designed to reduce emissions from deforestation and forest degradation, halt biodiversity loss, and provide equitable conservation benefits to people. Thus, carbon markets, including compliance carbon markets and voluntary carbon markets continue to expand in LATAM. However, the extent of the growth and status of forest carbon markets, pricing initiatives, stakeholders, amongst others, are yet to be explored and extensively reviewed for the entire LATAM region. Against this backdrop, we reviewed a total of 299 articles, including peer-reviewed and non-scientific gray literature sources, from January 2010 to March 2023. Herein, based on the extensive literature review, we present the results and provide perspectives classified into five categories: (i) the status and recent trends of forest carbon markets (ii) the interested parties and their role in the forest carbon markets, (iii) the measurement, reporting and verification (MRV) approaches and role of remote sensing, (iv) the challenges, and (v) the benefits, opportunities, future directions and recommendations to enhance forest carbon markets in LATAM. Despite the substantial challenges, better governance structures for forest carbon markets can increase the number, quality and integrity of projects and support the carbon sequestration capacity of the rainforests of LATAM. Due to the complex and extensive nature of forest carbon projects in LATAM, emerging technologies like remote sensing can enable scale and reduce technical barriers to MRV, if properly benchmarked. The future directions and recommendations provided are intended to improve upon the existing infrastructure and governance mechanisms, and encourage further participation from the public and private sectors in forest carbon markets in LATAM.

The possibility that the Amazon forest system could soon reach a tipping point, inducing large-scale collapse, has raised global concern1-3. For 65 million years, Amazonian forests remained relatively resilient to climatic variability. Now, the region is increasingly exposed to unprecedented stress from warming temperatures, extreme droughts, deforestation and fires, even in central and remote parts of the system1. Long existing feedbacks between the forest and environmental conditions are being replaced by novel feedbacks that modify ecosystem resilience, increasing the risk of critical transition. Here we analyse existing evidence for five major drivers of water stress on Amazonian forests, as well as potential critical thresholds of those drivers that, if crossed, could trigger local, regional or even biome-wide forest collapse. By combining spatial information on various disturbances, we estimate that by 2050, 10% to 47% of Amazonian forests will be exposed to compounding disturbances that may trigger unexpected ecosystem transitions and potentially exacerbate regional climate change. Using examples of disturbed forests across the Amazon, we identify the three most plausible ecosystem trajectories, involving different feedbacks and environmental conditions. We discuss how the inherent complexity of the Amazon adds uncertainty about future dynamics, but also reveals opportunities for action. Keeping the Amazon forest resilient in the Anthropocene will depend on a combination of local efforts to end deforestation and degradation and to expand restoration, with global efforts to stop greenhouse gas emissions.

The case study included approx. 0.5 million ha of forest areas in Poland that are managed by the Regional Directorate of State Forests. The objective was to assess the impact of four different scenarios restricting the size of forest areas available for commercial use. Based on different criteria, each scenario set aside 10% of the total land area for strict protection on forested land, which is in line with the EU Biodiversity Strategy 2030. The economic impact (volume of reduced wood raw material) was statistically estimated for each of the four scenarios. It was confirmed that the layout of forest habitats is essential for specific limitations in forest production. For the optimal implementation of the provisions of the strategy, a balance in the selection of social, economic, and natural elements must be considered. This protects primarily the most valuable natural habitats characterized by the highest level of biodiversity, age diversity, and dispersion within the studied forest unit. The presented results may support decision-making processes used to maximize biodiversity protection while minimizing the negative economic impact of this environmental protection. [ABSTRACT FROM AUTHOR]

Forests provide many ecosystem services that strongly depend on species diversity, as illustrated by the repeatedly observed diversity–productivity relationships (DPRs). These forest DPRs are assumed to result mostly from complementarity between species at the tree level whilst emerging community‐level processes remain poorly explored. In this study, we propose that the ‘tree packing effect’ (TPE), where species diversity promotes productivity by positively impacting maximum stand density, is an important determinant of DPRs. We tested the two components of TPE: (i) whether maximum stand density increases with species richness and (ii) whether this higher stand density allowed by species richness promotes forest productivity. First, relying on national forest inventories of six European countries (NFIs, totaling 2,367,776 trees), we fitted self‐thinning lines to examine whether these lines were influenced by plot species richness. We showed that maximum stand density increases with tree species richness in Europe, in all but one country. This trend was notably stronger in extreme climates. Second, we ran a large simulation‐based experiment (including 7,024,815 simulations) with an individual‐based forest dynamics model able to control for stand‐density effects, to quantify DPRs for more than 1000 sites in Europe. Relying on an original method to quantify DPRs at the site level, we compared the strength of DPRs simulated with and without control for stand density. We found positive DPRs up to 10‐times stronger when TPE is at play than when stand density is controlled. This positive effect of diversity on forest productivity through tree packing is also stronger in extreme climates, especially in warm and dry conditions. Synthesis. Highlighting the generality of the TPE in European forests, our results reveal that the effect of diversity on forest functioning is partly mediated by diversity‐driven changes in stand density. This mechanism has been long overlooked in biodiversity—ecosystem functioning studies, but our findings strongly call for its reconsideration, especially in natural forests. It also opens key perspectives for management and climate change mitigation programmes. [ABSTRACT FROM AUTHOR]

This study uses the Fire Weather Index (FWI) from the Canadian Wildfire Hazard Rating System (CFFDRS) to assess the danger of future wildfires in the Zagros Mountains under climate change. We use CanESM5 model data for the SSP245 and SSP585 scenarios to estimate FWI changes in the past (1960–2020), near future (2031 − 2017), and distant future (2061–2090). Statistical analysis at the 95% confidence level verifies significant differences in FWI values, especially in the Northwest. We explore spatial and temporal trends using Emerging Hot Spot Analysis (EHSA). The results show that cold spots are decreasing, and warm spots are increasing over time. The results of this study highlight the continuing dangers of wildfires in the region. The study underscores the significance of implementing preventive fire management strategies that consider the dynamic nature of weather patterns. [ABSTRACT FROM AUTHOR]

This essay explores the various types of spaces, primarily montane forested areas, where human access was restricted, either conditionally or entirely, during late imperial times. The range of restrictions always included felling trees, but often also encompassed other forms of extraction from local ecosystems. Based on the motivations for setting up and regulating such zones, it proposes a typology that includes imperial parks and graves, sacred sites, military exclusion zones, and certain forested commons. Based on some commonalities between these types, it concludes by reflecting on the place of notions of sacrality in local policies that directly impacted forested areas. [ABSTRACT FROM AUTHOR]

The research on forest ecological product (eco-product) value realization and ecological industry(eco-industry) has become a current hotspot. In order to facilitate scholars' understanding of the progress of existing research, this paper, based on 286 retrieved documents, statistically analyzes the research content, regional distribution, etc. And the following understandings were obtained: (1) The current volume of publications as a whole shows a trend of steady increase year by year, and China is the country with the largest volume of publications, accounting for more than half. (2) The research content mainly focuses on four aspects: supply capacity assessment, value accounting, value realization mechanism and eco-industry of eco-products. (3) It puts forward the problems of insufficient supply and slow development of industry at the present stage, deepens the deficiencies of the existing research and analyzes its inspiration for the future development of mountain forestation areas in rocky desertification control. Aims at providing forest practitioners and relevant decision makers with information for managing and regulating the supply capacity of forest eco-products and eco-industries. At the same time, it also provides ecological restoration technicians with a path to think about optimizing forest ecosystems for rocky desertification control. [ABSTRACT FROM AUTHOR]

This study examines the effectiveness of various spatial data sources and pathfinding algorithms for route determination in forested environments, focusing on the Mazovia region of Poland. Accurate and efficient forest route planning is critical for both military operations and crisis management, highlighting the need for reliable data and robust algorithms. The analysis centers on three primary spatial data sources that can support forest routing: the civilian Topographic Objects Database (TOD) and OpenStreetMap (OSM), along with the military-specific Vector Map Level 2 (VML2). Two commonly used pathfinding algorithms, Dijkstra and A* (the latter with six heuristic variations), were tested to assess their suitability and performance in these contexts. This study was conducted across ten of the largest forested areas in Mazovia, with route determinations performed between selected pairs of start and end points within each forest area. The findings indicate that the TOD database yielded the most stable and consistent routes, while the A* algorithm with Euclidean distance heuristics proved to be the fastest among the tested variants. In contrast, OSM data presented challenges due to inconsistencies, resulting in some routes being undeterminable, where connections between start and end points were lacking. These results underscore the importance of data quality and algorithm selection in effective forest route planning. [ABSTRACT FROM AUTHOR]

For an integer k ≥ 2 , a k - community structure in an undirected graph is a partition of its vertex set into k sets called communities , each of size at least two, such that every vertex of the graph has proportionally at least as many neighbours in its own community as in any other community. In this paper, we give a necessary and sufficient condition for a forest on n vertices to admit a k -community structure. Furthermore, we provide an O (k 2 ⋅ n 2) -time algorithm that computes such a k -community structure in a forest, if it exists. These results extend a result of Bazgan et al., 2018. We also show that if communities are allowed to have size one, then every forest with n ≥ k ≥ 2 vertices admits a k -community structure that can be found in time O (k 2 ⋅ n 2). We then consider threshold graphs and show that every connected threshold graph admits a 2-community structure if and only if it is not isomorphic to a star; also if such a 2-community structure exists, we explain how to obtain it in linear time. We further describe an infinite family of disconnected threshold graphs, containing exactly one isolated vertex, that do not admit any 2-community structure. Finally, we present a new infinite family of connected graphs that may contain an even or an odd number of vertices without 2-community structures, even if communities are allowed to have size one. [ABSTRACT FROM AUTHOR]

Summary Droughts of increasing severity and frequency are a primary cause of forest mortality associated with climate change. Yet, fundamental knowledge gaps regarding the complex physiology of trees limit the development of more effective management strategies to mitigate drought effects on forests. Here, we highlight some of the basic research needed to better understand tree drought physiology and how new technologies and interdisciplinary approaches can be used to address them. Our discussion focuses on how trees change wood development to mitigate water stress, hormonal responses to drought, genetic variation underlying adaptive drought phenotypes, how trees ‘remember’ prior stress exposure, and how symbiotic soil microbes affect drought response. Next, we identify opportunities for using research findings to enhance or develop new strategies for managing drought effects on forests, ranging from matching genotypes to environments, to enhancing seedling resilience through nursery treatments, to landscape‐scale monitoring and predictions. We conclude with a discussion of the need for co‐producing research with land managers and extending research to forests in critical ecological regions beyond the temperate zone. [ABSTRACT FROM AUTHOR]

A recent body of literature has documented the importance of environmental income to rural households in the Global South. However, this literature has not been analyzed to establish which findings are robust—what determines rural households' absolute and relative environmental income? We conducted a meta-analysis using published articles that measured environmental reliance from the Web of Science, Scopus, WorldCat.org, and MPDI databases. We examined the effect of socioeconomic, demographic, and resource site proximity variables on environmental income and reliance. We applied a meta-regression approach and included moderator variables such as sample size, survey frequency, and the types of journal to control for variations in effect estimates and assess risks of biases. We analyzed 112 studies published between 1996 and 2021 that together surveyed about 52,000 households in 35 countries. The findings confirmed that environmental income matters in total household income: environment, forest, and non-timber forest product reliance were, on average, 25 ± 11%, 27 ± 16%, and 27 ± 16%. The level of reliance was moderated by region and the type of environmental products. On average, the proportions of significantly negative, positive, and statistically insignificant effect estimates were 25%, 18%, and 57%. All covariates, except distance to the resource sites, were weakly correlated with environmental income and reliance, indicating no globally robust covariates. Thus, policies and interventions should build on regional specificities. [ABSTRACT FROM AUTHOR]

Forests play a key role in the carbon cycle, acting as major carbon sinks and important carbon stores on Earth. This article examines how forest ecosystems perform photosynthesis, the process by which they capture carbon from the atmosphere and convert it into organic matter. Particular attention is paid to the various mechanisms of carbon assimilation, such as the transformation of carbon into biomass, roots and soil, as well as its long-term storage. One of the main factors influencing the efficiency of carbon absorption is the forest type. For example, tropical forests, due to their high biomass and species diversity, absorb significantly more carbon compared to temperate and boreal forests. The influence of climatic conditions, such as temperature and rainfall, on the process of photosynthesis and tree growth is also considered. Forest age also plays an important role: young forests accumulate carbon faster, while old forests can reach a state where carbon accumulation slows down. The article also highlights the importance of preserving and restoring forest ecosystems as a strategic approach to combating climate change. Increasing forest area and implementing sustainable forest management practices can significantly increase their capacity to absorb carbon, as well as improve other ecosystem services such as maintaining biodiversity and protecting soil from erosion. Importantly, forest destruction caused by logging and land tenure change releases significant amounts of carbon into the atmosphere, exacerbating the problem of climate change. [ABSTRACT FROM AUTHOR]

ABSTRACT Background Aims Materials and Methods Results Discussion Conclusion The study of island species richness has gone far beyond traditional theories, as more and more studies attempt to include new predictor variables besides island area. Despite the rich bat diversity of Mediterranean islands, no studies have examined the factors influencing chiropteran species richness in such a geographic context.We used Greek islands as a model to detect drivers of bat species richness based on a broad species occurrence dataset from islands of the Aegean and Ionian Seas, which was explored using 10 potential predictor variables.Initially, we comprehensively evaluated all available data and sources for 53 Greek islands, deemed essential. This resulted in a reduced set of 28 islands. Predictors were grouped into three categories: island area, landscape diversity and island isolation. Generalised linear models were employed to identify the most significant factors explaining bat species richness in the 28 islands.Tree cover and the distance between the islands and their nearest coast (mainland or island) best performed to predict bat species richness on Greek islands.We show the important role of landscape composition and degree of isolation in influencing the distribution of bat species on islands.We highlight the importance of forest habitats and the vital role of their management and protection, especially in the insular systems of the Mediterranean basin, where the risk of forest degradation or loss due to wildfires and land use change is especially high. [ABSTRACT FROM AUTHOR]

The fraction of absorbed photosynthetically active radiation (FAPAR) is one of the bio-geophysical Essential Climate Variables assessed through remote sensing observations and distributed globally by space and environmental agencies. Any reliable remote sensing product should be benchmarked against a reference, which is normally determined by means of ground-based measurements. They should generally be aggregated spatially to be compared with remote sensing products at different resolutions. In this work, the effectiveness of various in situ sampling methods proposed to assess FAPAR from flux measurements was evaluated using a three-dimensional radiative transfer framework over eight virtual vegetated landscapes, including dense forests (leaf-on and leaf-off models), open canopies, sparse vegetation, and agricultural fields with a nominal extension of 1 hectare. The reference FAPAR value was determined by summing the absorbed PAR-equivalent photons by either all canopy components, both branches and leaves, or by only the leaves. The incoming and upwelling PAR fluxes were simulated in different illumination conditions and at a high spatial resolution (50 cm). They served to replicate in situ virtual FAPAR measurements, which were carried out using either stationary sensor networks or transects. The focus was on examining the inherent advantages and drawbacks of in situ measurement protocols against GCOS requirements. Consequently, the proficiency of each sampling technique in reflecting the distribution of incident and reflected PAR fluxes—essential for calculating FAPAR—was assessed. This study aims to support activities related to the validation of remote sensing FAPAR products by assessing the potential uncertainty associated with in situ determination of the reference values. Among the sampling schemes considered in our work, the cross shaped sampling schemes showed a particular efficiency in properly representing the pixel scale FAPAR over most of the scenario considered. [ABSTRACT FROM AUTHOR]

Basal metabolic rates (BMRs) increase with temperature and body mass. Environmental temperatures rapidly change in tropical mountains due to elevation (macro scale) and vegetation structure (micro scale). Thus, tropical mountains are good settings for testing the effects of temperature on BMRs. We measured the BMRs at four temperature ranges on six territorial and closely related species of Rubyspot damselflies (Hetaerina, Calopterygidae), which also share very similar behavior and morphology and are segregated by habitat and elevation across the Western Colombian Andes. We analyzed the effects of body mass, habitat, elevation, temperature, and sex on their BMRs, using a phylogenetic framework. We found that the main factors regulating their niche partition seemed to be environmental temperature, body size, and BMR. We found differences in their BMRs related to elevation when the temperatures were close to those experienced by the damselflies at their elevational range. As predicted, the larger species associated with colder habitats, forests, and highlands had higher BMRs. However, at high stressful temperatures, only the body mass was positively related to the BMR, showing that smaller individuals can keep their BMRs lower under high temperatures compared to bigger ones. Habitat use was not associated with changes in the BMR. Finally, phylogenetic reconstruction showed all species clustered in three clades. Each clade in the phylogenetic tree shares similar habitat preferences, pointing to a mixture of evolutionary history, thermal adaptations, and body mass differences as a possible explanation for the great diversity of these damselflies in a small area. Under the global warming scenario, we expect Rubyspots with smaller body sizes to be favored since they will tolerate higher temperatures, which would ultimately lead to populations with smaller body sizes overall, which could negatively affect their fitness. [ABSTRACT FROM AUTHOR]

The diversity of macrofungi has been closely associated with forest diversity and stability. However, such a correlation has not been established for the forests of the Ningxia Autonomous Region due to the lack of systematic data on its macrofungal diversity. Therefore, for the present study, we collected 3130 macrofungal specimens from the forests of the Helan Mts., Luo Mts., and Liupan Mts. in Ningxia and assessed them using morphological and molecular approaches. We identified 468 species belonging to 157 genera, 72 families, 18 orders, 11 classes, and 2 phyla. Among them, 31 species were ascomycetes, and 437 species were basidiomycetes. Tricholomataceae, with 96 species of 22 genera, was the most species-rich family, and Inocybe was the most species-rich genus (6.2%). The Jaccard similarity index measurement revealed the highest similarity in macrofungal species (16.15%) between the Helan and Liupan Mountains and the lowest (7.72%) between the Luo and Liupan Mountains. Further analyses of the macrofungal population of Ningxia showed that 206 species possess considerable potential for utilization, including 172 edible, 70 medicinal, and 36 edible–medicinal ones. Meanwhile, 54 species were identified as being poisonous. In these forests, saprophytic fungi were the most abundant, with 318 species (67.95%), followed by symbiotic fungi (31.62%) and parasitic fungi (0.04%). Grouping based on the geographical distribution indicated that the fungi of Ningxia are composed mainly of the cosmopolitan and north temperate types. These observations unveil the diversity and community structure of macrofungi in Ningxia forests. [ABSTRACT FROM AUTHOR]

This article explores the concept of resilience within the framework of fengshui forests in subtropical southern China over the last millennium. Consisting of small patches of old-growth or old secondary-growth forest associated with graves, temples, and the paths of wind and water into and out of villages, fengshui forests were historically seen as nodes that supplied vital qi (energy, force or substance) to the community, an understanding that persists to the present day. Using a combination of textual, ethnographic, and scientific evidence, we examine how these forests, deeply embedded in the cultural and ecological fabric of the region, have fostered community resilience and sustainability over centuries. We show that fengshui's vitalist and syncretic conception of the relationship among living people, ancestors, the land, and the trees allowed it to bridge Indigenous and imperial moral ecologies. By foregrounding both the emic and etic implication of fengshui, this article contributes to our understanding of Indigenous moral ecologies, the histories of social-ecological resilience, and the role of sacred forests in sustaining biodiversity and community well-being, past and present. [ABSTRACT FROM AUTHOR]

Many allometric models to predict tree aboveground biomass have been developed in tropical moist forests, but few models are available for tree belowground biomass. Theory predicts that belowground biomass scales in an isometric way with aboveground biomass. Estimates of belowground biomass could then be derived from aboveground biomass using the root:shoot ratio. Using a dataset of 118 tropical trees for which both aboveground and belowground biomass and other tree and species characteristics were measured in Gabon and Cameroon, we found a near isometric, yet significantly allometric, relationship between belowground biomass (B , in kilograms) and aboveground biomass (A , in kilograms): B  = 0.324 A 0.939. The root:shoot ratio was 0.20–0.22, regardless of tree size. An efficient model to predict belowground biomass from tree diameter (D , in centimeters), height (H , in meters) and wood density (ρ, in grams per cubic centimeter) was B  = 0.0188 (ρ D 2 H)0.977. A significant residual effect of species and leaf habit was found in this model, indicating that further tree and species characteristics are likely to explain additional variation in belowground biomass. Yet, the future development of belowground allometric models can benefit from the many models already developed for aboveground biomass. On the basis of this unprecedented sampling effort on tree belowground biomass in the dense tropical forests of the Congo Basin, we conclude that the scaling of belowground biomass with aboveground biomass should be the relationship to focus on. [ABSTRACT FROM AUTHOR]

Contestations around forests and lands have a long history in Sabah, Malaysia and the divergent interests of the ruling State, private business and indigenous and local peoples have played out in narratives shaping policies and debated in media since colonial times. Coalition building among actors is one avenue of influencing policy and securing benefits from policy outcomes. Here, we examine print media related to the Nature Conservation Agreement (NCA), a controversial carbon trading proposal, to identify policy coalitions based on actors' narratives about development and forests. Relevant articles from October 2021 to January 2023 were coded to identify the media frames, actors, and their arguments. Using discourse network analyser (DNA), three coalitions were identified: 1) Local rights defenders; 2) NCA promoters; 3) Process sceptics. Actors for or against the NCA both emphasise the importance of managing forests and local development within Sabah, but closer examination of arguments reveal that coalitions have different visions of who is to be included in decision-making and who will benefit from it. NCA promoters use the same narratives that have been historically used to legitimise state control over forests and land, and frame the NCA as an effective "win–win" solution for climate change and local economic development. The coalitions of dissenters highlight lack of transparency and free, prior, informed consent, and inequities for local and indigenous people. Discourses on development and resource management in Sabah are not without contestation, even though alternative options for more just development are still absent. [ABSTRACT FROM AUTHOR]

Quantitative assessment of organic carbon (OC) stocks in different habitats is crucial in ecology. Understanding the drivers affecting OC stocks across distinct carbon pools is essential for comprehending current patterns and predicting future changes. Alpine ecosystems, important for atmospheric CO2 regulation and highly vulnerable to climate change, are priority study areas. This research aims to estimate OC stocks in different pools (soil, organic horizons, and aboveground vegetation) and identify factors influencing these stocks in an alpine environment. We sampled 146 sites representing six forest types and two grassland types in the Gran Paradiso National Park (northern Italian Alps). Field samples of soils, organic horizons, and data on aboveground trees were collected to assess OC stocks, along with environmental variables. Our findings reveal nuanced variations in OC stocks across different ecosystem components. In grasslands, average soil OC was 5.57 kg m−2, while in forests it was 4.11 kg m−2. Organic horizons contained an average of 0.70 kg m−2, and aboveground vegetation in forests stored 6.61 kg m−2. Linear Mixed Models indicate that soil OC is influenced by habitat type, soil type, and elevation. OC in organic horizons is affected by aspect and forest habitat type, with composting further influenced by elevation. These results contribute to OC stock inventories for alpine ecosystems and enhance our understanding of how environmental factors influence carbon storage. Importantly, they underscore the need to consider soil type and other factors beyond land use when modeling OC stocks. This insight has implications for designing effective territorial strategies to address climate change, emphasizing the importance of a multifaceted approach to carbon stock assessment and management in alpine regions. [ABSTRACT FROM AUTHOR]

Currently, people are more and more willing to rest in areas of urban greenery or forest areas for relaxation, sports, tourism, or recreation. Nonetheless, the decision for this type of activity is often a thoughtful, planned decision that determines the level of quality of life. The purpose of our study was to determine whether objective indicators of quality of life, such as social, economic, infrastructural, and environmental factors, influence the frequency of visits to urban green areas and forest areas. An online survey was conducted by a professional firm on a group of 1000 people living in and around the Warsaw metropolitan area. The results showed a clear seasonal pattern, with a higher frequency of visits in summer compared to winter. Urban green areas were more likely to be visited than forests. The frequency of visits was influenced by the 11 analysed factors, although not always in all variants. Among these factors were education level, income, distance to urban green areas, and assessment of the quality of greenery at the place of residence. Women and younger age groups were more frequent visitors, especially in summer, while older people and lower-income groups visited less often, especially in winter. The results underscore the importance of integrating green spaces with urban planning to increase accessibility and meet the diverse needs of the population, promoting both physical and mental well-being. Further research should be extended to other metropolitan areas and exploring psychological motivations for visiting natural areas. [ABSTRACT FROM AUTHOR]

Urban and peri-urban forests serve as significant drivers, conferring benefits to humans through engagement with their ecosystems. These benefits encompass recreation, cognitive development, introspection, the acquisition of knowledge systems, social relations, and aesthetic values. The aim of this study is to examine the urban and peri-urban ecosystem services by offering new insights into visitors' perspectives on the recreational, aesthetic, and spiritual values of forests in the city of Timișoara and its peri-urban area. The study focuses on two forests: Padurea Verde, the largest forest in Timișoara, and the Giroc Forest, one of the most frequently visited forest areas in the peri-urban zone of Timișoara. Thirty-six in-depth interviews were conducted with visitors to the two selected forests in September 2024. The findings indicate that visitors derive benefits from the ecosystem values of these forests, including recreational, aesthetic, and cultural values. However, there are also feelings of disappointment related to the lack of cleanliness and the presence of an excessive number of stray dogs in the forests. The findings also indicate a necessity for the implementation of organized activities, such as sports competitions and more children-oriented events, while discouraging the organization of festivals and the excessive use of noise in forests. Furthermore, they suggest that forests should be maintained in a relatively undisturbed state. These findings could prove beneficial as future perspectives for local practitioners, enabling the continued provision of complex ecosystem services and recreational values by urban and peri-urban forests. [ABSTRACT FROM AUTHOR]

The amplification effect of anthropogenic‐biogenic interactions on secondary organic aerosol (SOA) formation remains debated, particularly regarding the impact of anthropogenic emissions on biogenic SOA (BSOA) formation in forests near megacities. This study concurrently measured typical biogenic and anthropogenic SOA tracers during day and night at the summit (1,690 m a.s.l.) and foot (200 m a.s.l.) of the Nanling mountains, a large subtropical forest adjacent to the Pearl River Delta (PRD) in southern China. Results revealed unexpectedly high concentrations of BSOA tracers (149.9 ± 70.5 ng m−3 at the summit and 109.7 ± 51.2 ng m−3 at the foot), surpassing those at most other background sites worldwide. Daytime BSOA tracer levels at the foot were consistent with nighttime levels, whereas the summit showed significantly higher concentrations at night. Nighttime correlations between O₃ and BSOA tracers at the summit suggest that high O₃ levels stimulate BSOA formation. Conversely, a negative correlation between O₃ and isoprene derived SOA (SOAI) tracers at the foot indicates that other oxidants may also influence SOAI formation. BSOA tracer concentrations rose significantly with the arrival of anthropogenic pollutants (e.g., SO₂ and NO₂), indicating that anthropogenic pollution amplifies BSOA formation by enhancing aerosol acidity (pH < 3). This amplification effect could be mitigated by the reduction of aerosol acidity due to increased NH₃ and relative humidity (RH). Our findings provide valuable insights into the interactions between anthropogenic and biogenic emissions on SOA formation and vertical distribution in forests surrounding megacities. Plain Language Summary: Secondary organic aerosol (SOA) makes up a significant portion of global submicron‐sized atmospheric organic aerosols (OA), reaching up to 90% by mass. Understanding its composition and sources is essential for improving air quality and adapting climate change. However, the role of interactions between human‐made (anthropogenic) and natural (biogenic) emissions in enhancing SOA formation is still debated, especially near megacities. To investigate this, we measured biogenic and anthropogenic SOA tracers simultaneously at the summit (1,690 m a.s.l.) and foot (200 m above sea level) of the Nanling mountains, a subtropical forest near the PRD in southern China, during both day and night. Our results showed unexpectedly high concentrations of SOA tracers compared to most global sites. Isoprene‐derived SOA tracers were predominant at the summit, while monoterpene‐derived SOA tracers were more prevalent at the foot. Interactions between anthropogenic and biogenic emissions can enhance biogenic SOA formation in forested areas near megacities, although this effect can be mitigated by increase of ammonia (NH3) and RH. Also, ozone played a crucial role in nighttime biogenic SOA formation at the summit. These findings highlight the impact of anthropogenic‐biogenic interactions on SOA formation and its vertical distribution in urban‐adjacent forests. Key Points: Diurnal patterns of secondary organic aerosol (SOA) tracers were simultaneously investigated at the summit and foot of Mt. NanlingSOA tracer concentrations were found to be significantly higher than those at most other background sites worldwideInteractions between anthropogenic and biogenic emissions amplified SOA formation in forests near megacities, particularly during pollution periods [ABSTRACT FROM AUTHOR]