Climate variability, tree diversity and stand structure jointly regulate biomass carbon dynamics in two subtropical forest stands representing contrasting successional stages in eastern China

Sealed surfaces limit bird diversity, whereas tall structures may support abundance of some species, while both filter traits in urban landscapes

Bird biodiversity in vegetation along unpaved rural roads in Central European farmland

Mechanical damage markedly modifies the emission patterns of green leaf volatiles (GLVs), which serve as key signaling compounds in plant defense, yet interspecific variations across diverse tree species and their linkage to ecological adaptation remain poorly characterized. This study systematically analyzed GLVs (aldehydes, alcohols, esters) in 45 tree species (19 deciduous, 26 evergreen) under both intact and mechanically wounding conditions, integrating leaf functional traits and ecological strategy types. Intact leaves emitted low levels of GLVs, primarily esters. Wounding increased total emissions 5- to 200-fold, with alcohols and aldehydes rising most sharply; over 80% of post-wounding compounds were newly induced. Deciduous species exhibited significantly higher GLVs emissions and wound responsiveness than evergreens. GLVs emissions correlated closely with leaf dry mass per area (LMA, negative) and leaf water content (LWC, positive), and differed among ecological strategy types. Wounding enhanced synergies between GLVs, monoterpenes, and aromatic compounds within the BVOC blend, forming an integrated defense network whose structure depended on life form. GLV emission patterns also aligned with species' dominant volatile metabolism: isoprene emitting deciduous trees showed intense aldehyde bursts, whereas monoterpene emitting evergreens maintained stronger ester monoterpene coupling. Our findings demonstrate that mechanical injury reprograms GLV emissions in a trait- and strategy-dependent manner, reflecting evolutionary trade-offs between growth and defense. This study provides a trait-based physio-ecological framework that links leaf economics, volatile metabolism, and network-level coordination, offering a mechanistic basis for selecting stress-resilient trees and refining forest emission models under environmental disturbance.

Forest ecosystem restoration often focuses on the recovery of tree diversity and carbon stocks, with minimal attention given to soil microbial communities. Given the essential role of soil microorganisms for ecosystem health and recovery, this lack of understanding may limit reforestation success. In this study, we address this gap by analysing the taxonomic and functional characteristics of fungal and bacterial communities in minimally managed Acacia mangium plantations, especially considering their role in carbon sequestration and ecosystem functioning. We sampled naturally regenerating Acacia mangium plantations aged 2, 10, and 24 years, grasslands of Imperata cylindrica as the baseline condition, and remnant forests as reference state. We identified soil fungal and bacterial taxa through high-throughput amplicon sequencing of soil environmental DNA (eDNA), targeting ITS and 16S rRNA metabarcoding markers. Our results showed that microbial community and functional groups composition differed among landcover types, although taxonomic richness did not. Bulk topsoil organic carbon, pH, and total nitrogen were key factors associated with the composition of microbial communities, especially dominant fungal phyla. Symbiotrophic fungi and copiotrophic bacteria generally increased and recovered over time, potentially enhancing carbon (C) sequestration and balancing nutrient cycles. These findings demonstrate that natural regeneration in A. mangium plantations can promote the recovery of soil microbial communities and their associated functions, including those relevant for climate change mitigation. Furthermore, our study highlights the effectiveness of eDNA and high-throughput sequencing in monitoring early ecosystem shifts in soil microbial communities, which could be used to guide reforestation efforts towards desired ecosystem services.

Secondary succession forests are a fundamental component in the recovery of the structure and functionality of tropical ecosystems. The objective of this study was to evaluate the tree component and quantify the above-ground carbon storage in the secondary succession forest of the San Mateo recreational complex, in the Las Naves district, Bolívar province, Ecuador. The research was conducted using a descriptive quantitative approach, establishing three 1,000-square-metre transects in the study area, where all tree individuals with a diameter at breast height equal to or greater than seven centimetres were recorded. A total of 150 tree individuals with DBH ≥ 7 cm were identified, distributed across 23 species and 13 families. The most abundant species were Castilla elastica (15.33%), followed by Miconia bolivarensis (12.00%) and Ocotea insularis (10.00%). In terms of atmospheric carbon, 503.76 TmC was obtained, with Castilla elastica being the species with the highest carbon capture capacity (92.57 TmC/ha). In addition, the Shannon index indicated average diversity (2.73), while the Simpson index showed high diversity (0.91). In conclusion, the forest has a diverse tree structure and a high carbon storage capacity.

Although competition and facilitation both influence tree diversity1-5, their relative importance and variation with latitude remain poorly understood. Using data from 17 large forest plots, including around 2.7 million trees and over 5,400 species spanning 5° S to 47° N, we quantified the latitudinal trends of the relative importance of negative (competitive) and positive (facilitative) interactions among neighbouring tree species, accounting for three biotic and eight environmental factors. We examined whether the average neighbourhood species diversity around individuals of each focal species was larger or smaller than expected under null models. Theresults show that negative interspecific interactions prevailed across most plots. Near the equator, the relative proportions of species surrounded by a lower or higher than expected number of neighbours were roughly equal, but at higher latitudes, the proportions of species with a relatively higher number of neighbours declined, and those with fewer neighbours increased significantly. This latitudinal pattern can be attributed in part to reduced abundance of legumes, non-arbuscular mycorrhizal associations, and the weaker canopy nursing effect towards higher latitudes, but itwas mediated by mean annual temperature. These findings reveal a previously unrecognized relative decline in facilitative interactions and increase in competitive interactions with latitude and suggest that rising temperatures could enhance facilitative effects and promote tree community diversity at higher latitudes.

Anthropogenic Factors Dominate Taxonomic Diversity of Urban Street Trees While Climate Drives Phylogenetic Diversity

Deforestation reshuffles communities across landscapes with myriad consequences for ecosystem function. Following deforestation, rapid exposure to novel microclimates can act as a strong environmental filter, favoring warm-adapted species and decoupling trophic interactions. Forest restoration may partly reverse this process through increased food resources, structural complexity of habitat, and buffering of microclimates-each potentially modified by tree diversity. Despite growing evidence that tree diversity and cool microclimates help maintain animal diversity in natural forests, less is known about how these factors shape species assemblages or multi-trophic dynamics in restoration areas. Here, using surveys and two field experiments within a long-term tree planting experiment, we assessed the relative effects of tree diversity, forest structure, and associated microclimate on fine-scale space use by birds and their top-down impacts on insects. Surveys showed that the probability of occurrences of birds increased in cooler plots, which were associated with higher tree diversity and vertical complexity. The strength of microclimate effects on bird occurrences was strongest for species that are forest specialists. To assess risk to insect herbivores from avian predation, we used a sentinel prey experiment and found that predation risk increased in warmer plots, counter to our expectations based on bird surveys. Last, we examined top-down effects of bird exclusion on leaf herbivory, finding that skeletonizing patterns of herbivory increased in exclosures and in cooler plots. Taken together, these results suggest that microclimate resulting from variation in forest structure shapes the space use of birds at fine scales with complex outcomes for bird-herbivore-tree interactions in planted forests. Active restoration methods that enhance below-canopy cooling may improve biodiversity outcomes and help maintain species interactions that underlie many ecosystem functions.

Tree community composition modulates early-stage decomposition of standard litter through chemical and physical engineering

Climate change is impacting forests in Central Europe, causing increased mortality and degradation of forest ecosystem services (FES). As global warming intensifies, these effects are likely to worsen, particularly through more severe droughts and increased biotic disturbances. Understanding how forests respond to different levels of warming is essential for adaptation planning. Therefore, this study analyzed changes in forest structure and FES, including timber production, climate change mitigation, recreation, and structural diversity, under three global warming scenarios. Using the LandClim model, we compared warming levels of 1.5, 2, and 3 ​°C above pre-industrial temperatures, based on 30-year periods from RCP data, to historical climate. Our research focused on Freiburg's forests in southwestern Germany, characterized by diverse tree species and an elevation range of 200–1,250 ​m a.s.l. A warming of 1.5 ​°C could temporarily increase productivity, but at 2 ​°C, biomass losses of up to 10% would occur below elevations of 450 ​m due to drought mortality. Under 3 ​°C, losses would intensify below 650 ​m up to 40%, with even drought-resistant species like pedunculate oak experiencing mortality. At higher elevations, bark beetle outbreaks caused mortality of Norway spruce, while European beech capitalized on the changing ecological conditions. Higher warming levels significantly deteriorated FES, particularly timber production, climate change mitigation, and structural diversity, while recreation was less affected. These findings emphasize the urgency of meeting Paris Agreement targets, as limiting warming below 2 ​°C can reduce severe impacts. If warming exceeds this critical threshold, even species presently considered drought-resistant, such as native sessile and pedunculate oaks and non-native red oak, could face serious threats at lower elevations. This would undermine the effectiveness of current management strategies, as these tree species are key to providing multiple FES.

The CONSTANS, CONSTANS-like, and TIMING OF CAB EXPRESSION 1 (CCT) domain proteins are key regulators of flowering time and circadian rhythms in annual plants, but their diversity and temporal expression patterns in perennial trees remain poorly understood. Here, we performed a genome-wide characterization of CCT family genes and analyzed their seasonal and circadian expression dynamics in Populus. Using an HMM-based search, we identified 49 putative CCT genes (PtCCTs) in the Populus genome and classified them into five subfamilies (COL, CMF, PRR, ALSM and ZIM) based on domain composition and phylogeny. Synteny and duplication analyses showed that most PtCCTs arose from segmental duplication and have predominantly evolved under purifying selection. Promoter analyses revealed a rich repertoire of cis-regulatory elements, with a marked enrichment of light- and hormone-responsive motifs, particularly G-box and ABRE elements, in PtPRR and a subset of PtCOL promoters. Transcriptome data indicated that many PtCCTs display distinct tissue-specific expression patterns, with PtPRRs and PtZIMs being strongly enriched in dormant buds. Seasonal transcriptomes from leaves and shoot apices revealed discrete expression profiles associated with growth, bud set, and winter dormancy, and most PtPRRs showed increasing transcript levels from September to December. Diurnal time-series data further identified 19 PtCCTs with significant rhythmic expression, separating COL and PRR members into night- and day-phased groups. Network analysis using STRING indicated that PtPRRs interact with photoperiodic pathway components such as PtGI, and re-analysis of diurnal data from wild-type and lhy-RNAi hybrid aspen showed that several PtPRRs exhibit phase and amplitude changes when LHY expression is reduced. Together, these results provide a comprehensive overview of the CCT gene family in Populus and highlight PtPRRs and specific PtCOLs as promising candidates that link the circadian clock and light signaling to seasonal growth cessation and bud dormancy in perennial trees.

Cocoa-based agroforestry systems (AFS) are a key strategy for strengthening agronomic and economic sustainability in tropical regions; therefore, comprehensive knowledge of their structure and performance is essential. This study characterized 12 cocoa-based agroforestry plots in the Utcubamba province, Amazonas (Peru), through an integrated field assessment that included tree inventory and structural measurements, soil laboratory analysis, pest and disease surveys, and economic evaluation. Tree diversity and structure revealed functionally differentiated communities, reflected in Shannon index values of H′ = 2.24, canopy cover exceeding 60%, and importance value indices (IVI) highlighting dominant species such as Calycophyllum spruceanum (16.79%) and Laurus nobilis (15.64%), which contribute to microclimatic regulation and system resilience. Soil analyses showed strong correlations among soil organic carbon (SOC), soil organic matter (SOM), and total nitrogen (N) (r > 0.95), emphasizing the role of organic matter management in improving soil quality and crop productivity, with SOC ranging from 1.91% to 3.89%, SOM from 3.30% to 6.71%, and total N from 1.65% to 3.35%. Pest incidence exhibited low or insignificant correlations with soil parameters (r ≤ 0.32) and generally moderate levels, suggesting a stronger influence of management practices and shade structure. Economically, the systems showed an average annual net benefit of USD 2,616.91 per hectare per year and a benefit–cost ratio of 2.30, indicating positive economic performance. Overall, cocoa-based AFS function as productive systems capable of maintaining agronomic performance while generating economic profitability under the evaluated conditions.

Amazonian large trees act as central elements of forest ecosystems, storing a disproportionate fraction of aboveground biomass. However, these trees are not randomly distributed across the landscape, and it is expected that edaphic attributes influence floristic composition, forest structure, and vegetation biomass. In this study, we investigated how variation in soil chemical and physical properties affects the diversity and biomass of large trees. Forest inventories were conducted at five sites within protected areas in the states of Pará and Amapá. Aboveground biomass was estimated using allometric equations, while soil samples were analyzed for their physical and chemical properties. Diversity indices, rarefaction, Redundancy Analysis, and Generalized Additive Models were applied. Edaphic variables such as soil pH, organic matter, phosphorus, and aluminum were associated with floristic composition and the biomass of these individuals. Trees with a diameter at breast height greater than or equal to 70 cm accounted for up to 80% of total biomass, revealing a pattern of biomass hyperdominance. The results indicate that the occurrence of large trees is related to edaphic and structural attributes, such as tree density and size distribution, suggesting that these individuals are not randomly distributed along soil gradients. Understanding these patterns is essential for improving ecological models, biomass extrapolations, and management strategies aimed at conserving the Amazon rainforest.

Erratum for the Research Article, "Mycorrhizal symbioses and tree diversity in global forest communities" by F. Jiang et al.

The Brazilian Atlantic Forest, a critical biodiversity hotspot, plays a vital role in climate regulation and water conservation. To explore the relationship between tree diversity and soil bacterial communities, soil samples were collected along an edapho-climatic gradient. We hypothesized that tropical forest soils, among Earth’s most complex biological environments, exhibit predictable microbial community assembly patterns driven by deterministic processes. Specifically: (i) tree composition influences bacterial communities more strongly than abiotic factors when environmental heterogeneity is low, following niche-based assembly rules; (ii) specific tree taxa function as keystone species, shaping bacterial communities through microhabitat modification. Our findings indicate that tree diversity had a greater influence on shaping bacterial communities than soil attributes. Of the 72 tree species identified, Senegalia recurva, Araucaria angustifolia, Styrax acuminatus, Ilex paraguaiensis, Eugenia subterminalis, and Pisonia ambigua were key drivers of soil bacterial diversity. Additionally, late-successional tree species that require high light were closely linked to predicted microbial cycling of carbon, nitrogen, sulfur, and phosphorus. These results offer a hypothesis-generating framework for evaluating species selection in Atlantic Forest restoration projects, suggesting that these species represent candidates whose effects can enhance soil health and ecosystem functionality in reforestation programs.

Biodiversity is essential for maintaining ecosystem functionality, ensuring food security, regulating climate, and sustaining human well-being. Yet, in neglected biomes, biodiversity is often lost before many species can even be identified or studied. In Brazil, the Cerrado stands out as the most flora diverse savanna on the planet, but it remains critically underexplored. To address this gap, the National Forest Inventory (IFN) carried out an unprecedented, systematic sampling across the Brazilian Cerrado. Using 1803 tree-inventoried vegetation plots across the most biodiverse savanna on earth, we offer a first biome-wide assessment of tree diversity across the Brazilian Cerrado. We mapped tree species richness and alpha-diversity at 0.1-degree resolution and investigated their environmental drivers. Using only spatial location, stratified by vegetation formation, our LOESS-based model provides the most spatially detailed assessment of tree diversity across the Brazilian Cerrado to date, explaining approximately 47% of the observed variation in tree species richness. The south-western and central-western regions of the Brazilian Cerrado exhibited the highest tree biodiversity. Tree species richness was positively associated with broad-scale precipitation, temperature gradients, and soil clay content, whereas it declined with increasing fire frequency, soil bulk density, and soil aluminium concentration. Our results reveal marked spatial patterns and key environmental drivers of tree diversity across the Brazilian Cerrado, providing a valuable foundation for future biodiversity assessments and evidence-based conservation planning throughout the biome.

Tree-based production systems embedded within Amazonian biocultural landscapes remain systematically undervalued in global climate, biodiversity, and development policy frameworks. This study assessed tree diversity, structural attributes, and carbon stocks across traditional cacao-based Amazonian agroforestry systems (Chakra), tree-rich silvopastoral systems, and old-growth forests in the Andean–Amazon transition zone of Ecuador. Based on 28 sampling plots (DBH ≥ 10 cm), old-growth forests stored the highest aboveground carbon stocks, while agroforestry and silvopastoral systems retained approximately 20–30% of forest carbon, equivalent to ~100–180 Mg CO2-equivalent ha−1—far exceeding values reported for monocultures or treeless pastures. A total of 151 tree species were recorded across all land-use systems, with forests harboring the highest richness (122 species), followed by agroforestry (35 species) and silvopastoral systems (28 species). Carbon storage was highly concentrated in a limited subset of multifunctional species: in agroforestry systems, eight species accounted for ~80% of total aboveground CO2-equivalent stocks, whereas in silvopastoral systems only five species explained a similar proportion. Dominant taxa such as Cordia alliodora, Inga edulis, Jacaranda copaia, Piptocoma discolor, and Piptadenia pteroclada illustrate a process of biocultural species filtering, whereby trees providing food, timber, shade, and cultural value are selectively retained while sustaining significant carbon stocks. These findings demonstrate that tree-based productive systems function as biocultural productive landscapes that conserve carbon, biodiversity, and livelihoods beyond forest boundaries. We argue for their formal inclusion, particularly traditional silvopastoral systems, within climate finance mechanisms, nationally determined contributions (NDCs), and biocultural heritage frameworks, alongside forest conservation strategies.

Effects of mycorrhizal dominance on species diversity and carbon stock in a large temperate forest region.

Is beta diversity higher in seed plants with larger body sizes?