Deadwood fungi are extremely diverse and crucial for carbon turnover in forests. To achieve multifunctional forests, we need to better understand the relationships between diversity, management, and ecosystem processes. We tested the effects of forest structure, i.e. canopy cover and deadwood enrichment, on fungal diversity and mass loss of European beech and Scots pine. We additionally assessed the effects of fungal diversity on mass loss. We expected deadwood enrichment to better explain fungal diversity, while canopy cover, alongside fungal diversity, would best explain mass loss. Overall, host tree species was more important than forest structure in explaining diversity. Beech fungal diversity was higher under closed canopies, while pine fungal diversity increased with some types of deadwood enrichment. Surprisingly, beech mass loss was higher in stands without deadwood enrichment, but also where tree crowns were added. Pine mass loss was not affected by forest structure. Effects of fungal diversity on mass loss were significantly related to fungal community composition in pine. Our findings emphasize the need for diverse tree hosts at the forest landscape-scale. However, contrasting diversity and decomposition effects between host trees indicate that stand-scale management strategies should be tailored to tree species to maintain diversity and decomposition processes.

Plant diversity is known to enhance soil resource availability and productivity through niche partitioning and facilitation; however, existing studies have predominantly examined these effects at the community level. The role of tree neighborhood diversity in alleviating nutrient limitations remains unclear. Here, using a tree diversity experiment in a subtropical forest with naturally low phosphorus (P) availability and depleted soil base cations, we evaluated how neighborhood diversity helps alleviate nutrient co-limitation. We found that greater neighborhood phylogenetic and trait dissimilarities enhanced growth rates and increased foliar P and magnesium (Mg) concentrations, as well as resorption efficiency in focal trees. Foliar Mg exhibited a more pronounced response than P and calcium (Ca), suggesting that diverse communities may prioritize alleviating Mg limitation over other nutrient limitations. Elevated foliar Mg concentration in focal trees were positively correlated with foliar transpiration, both driven by greater neighborhood phylogenetic dissimilarity. Our findings demonstrate that neighborhood diversity is essential in mitigating nutrient limitations on tree growth, highlighting the importance of phylogenetic and functional trait dissimilarities in mediating these positive effects.

Introduction Ancient trees are keystone ecological and cultural entities ancient that provide essential services to humans in settlements. The unique natural and cultural geography in the China-Vietnam border region provides relatively undisturbed habitats for ancient trees. Cross-border activities, policy disparities, and uneven conservation resources currently challenge their survival and diversity. Methods A study was conducted in Chongzuo city, a typical border city, to quantify the species diversity, abundance and distribution of ancient trees, and their relationship with varied habitats. Redundancy analysis (RDA) identified the primary factors influencing their spatial patterns. Results The results identified 15,722 ancient trees from 99 species, 73 genera and 35 families. Twenty-nine species were solitary with only one individual each, and 14 were listed as protected plants in China. The population was dominated by Camellia drupifera , Ficus altissima , Dimocarpus longan , and Excentrodendron tonkinense , collectively accounting for 84.05% of the recorded trees. Ancient trees decreased with tree age, height, DBH, and crown width, with the majority (95.33%) in the 100–299 years age group. More natural habitats, including mountains, villages, and farmlands, supported the highest trees abundance, while parks, nature reserves, and scenic spots accommodated the greatest species richness. Pingxiang township had the highest tree abundance (9,118), while Longzhou had the highest species richness (50). Ningming, however, had the largest Shannon-Wiener index ( H = 2.42), making it the most important district for preserving tree diversity. Land area, built-up area, GDP, population density, forest coverage, farmland area, and altitude significantly influenced the distribution of ancient trees. Discussion The inherently high landform and habitat diversities in the study area support many ancient tree species. Due to the complex terrain, in-depth, long-term, and systematic research remains relatively scarce. Future studies could integrate natural and anthropogenic factors to explore the survival patterns and conservation needs, allowing the formulation of targeted strategies for their sustainable protection.

Human activities are driving simultaneous native extinctions and alien naturalizations, reshaping global tree diversity with major implications for ecosystem structure and function. Here we analysed functional traits and environmental niches of 31,001 tree species worldwide, comparing naturalized, threatened and non-threatened species to assess current patterns and project future shifts under intensified extinction and naturalization. Future tree-rich ecosystems are projected to become increasingly dominated by fast-growing, high-resource-use species with acquisitive traits, while slow-growing, conservative species face greater extinction risk. Although group means along the main functional axes do not differ significantly, naturalized species occupy broader functional and environmental spaces and thrive in colder and more variable climates, whereas threatened species are more specialized to warm, stable and nutrient-rich environments, with non-threatened species intermediate. Projected naturalizations expand local functional diversity, but their acquisitive strategies could reduce long-term ecosystem stability, while extinctions cause pronounced contractions of functional and environmental trait space, especially in climatically variable regions. Overall, our findings reveal an accelerating global shift towards faster-growing tree communities, with likely consequences for carbon storage and biodiversity, underscoring the need to safeguard slow-growing species and limit the dominance of acquisitive trees.

Abstract Climate change is increasing the probability of wildfires in the non-fire-prone forests of Central Europe. Systematic knowledge on tree resistance to fire would help to improve the future management of forests to ensure their long-term adaptation to climate change impacts. However, a systematic classification of the fire resistance of tree species occurring in Central Europe remains largely unexplored. While observations from surface-fire-dominated ecosystems show that bark constitutes an important interface between fire and tree physiology, the influence of bark traits remains an open question, due to conflicting study results. To address this gap, we conducted heating experiments on stem discs with intact bark, assessing bark thermal conductivities of six tree species common in Europe (the native species Abies alba, Fagus sylvatica, Larix decidua, Picea abies, Pinus sylvestris, and the non-native Pseudotsuga menziesii ). By applying generalised additive models, we further investigated the influence of bark traits (thickness, moisture content, density), relative height along the tree stem, and tree species identity on insulation capability. Our results indicate that bark thickness may be the most robust predictor for assessing bark-related resistance to surface fires (i.e. insulation capability). A decrease in thermal resistance was observed with increasing relative height of the sample along the tree stem. Further, we found evidence for decreasing thermal resistance with increasing bark moisture content, but no significant effect of bark density on bark insulation capability. We identified significant interspecific differences in bark insulation capability between the investigated tree species, particularly in combination with species-specific patterns of bark investment. Accordingly, our results suggest higher resistance to fire for L. decidua , P. menziesii , and P. sylvestris , while A. alba , P. abies , and especially F. sylvatica may be associated with lower fire resistance. Our results underscore the need to incorporate diverse tree species' characteristics into assessments of disturbance resistance in the face of climate change.

The variation of structural and compositional characteristics of urban forests is influenced by the urban landscape heterogeneity and several biotic, abiotic, and human factors. Urban forests provide numerous ecosystem and social benefits key to the wellbeing of citizens and to enhance environmental conditions in cities. However, the quantity and quality of these services are determined by the urban forest structure, composition, and spatial variation. There has been little research on the heterogeneity in the urban forest structure and composition across the entire urbanized area of Mexico City, one of the largest and most populated cities in North America. This study explores urban forest composition, diversity and structure across the entire urbanized area and within six urban land uses and the 16 boroughs of Mexico City using tree data from 500 fixed-area plots of 400 m2 distributed across the city. Alfa and beta diversity analysis, and analysis of variance revealed differences in tree diversity and structure within land uses and boroughs. Green areas had higher basal area but less species richness than the residential and the commercial-residential land-use types. The lower values of basal area and canopy cover were found in the boroughs in the east part of the city, and the highest species richness was in boroughs in the south. Land use types and boroughs are ecologically heterogeneous units (β = 0.5, β = 0.6, respectively) and urban forest planning needs to consider their specific conditions. The higher proportion of non-native species found in this study highlights the need to diversify prioritizing native species.

Wood density is a key plant property, indispensable for estimating forest biomass. Yet, despite tropical regions' substantial contributions to global tree diversity and carbon cycling, they remain underrepresented in wood density datasets such as the CIRAD and Global Wood Density Database (GWDD). To address this gap, we present the 'Tervuren xylarium Wood Density Database' (TWDD), containing 13,332 samples from 2,994 species, 1,022 genera, and 156 plant families across six continents (72% from Africa). TWDD offers direct measurements of oven-dry (oven-dry mass/oven-dry volume, all samples), air-dry (air-dry mass/air-dry volume, 6,408 samples), green (green mass/green volume, 1,657 samples), and basic wood density (oven-dry mass/green volume, 1,686 samples). Basic density was estimated for the remaining 11,646 samples via conversion from oven-dry density. TWDD closes a substantial wood density data gap, especially in Africa, adding 1,164 new species, 160 new genera, and 8 new plant families not included in GWDD or CIRAD datasets. The TWDD provides a critical resource for advancing research on forest community dynamics, ecosystem functioning, carbon cycling, and trait-based ecology worldwide.

Biodiversity-ecosystem functioning (BEF) research has shown that ecosystem functioning and stability are closely linked to biodiversity. A cornerstone of this field is the BEF-China research platform, i.e. the world’s largest forest biodiversity experiment in subtropical China. It has demonstrated that tree diversity enhances productivity, carbon sequestration and ecosystem stability. However, the strength of these positive tree diversity effects varies widely across forests, possibly because higher trophic levels (such as herbivores and predators) mediate how biodiversity influences ecosystem functioning. To better understand how tree diversity influences higher trophic levels and their contributions to forest functioning, the German Research Foundation (DFG) is funding the project MultiTroph . MultiTroph quantifies species interactions and integrates them into food webs to understand when and why ecosystem functions change or destabilise with species loss. We expect that trophic interaction networks reveal how species share or separate their ecological roles, with more niche overlap in species-rich forests and more niche specialisation in species-poor forests. Here, we outline our conceptual framework and research goals. We are convinced that MultiTroph will expand existing BEF research and provide a more holistic understanding of the role of multi-trophic food webs in forest ecosystems.

IntroductionUnderstanding the synergies and trade-offs among tree, understory, and soil carbon pools is critical for optimizing forest carbon sinks. However, the mechanisms regulating these relationships, particularly how they differ between natural and planted forests, remain unclear. This study aims to deconstruct these complex interactions in subtropical forests to provide a scientific basis for enhancing ecosystem carbon storage.MethodsBased on data from 440 plots covering six major forest types in subtropical China, we employed linear mixed-effects models (LMMs) to quantify universal and context-dependent driver effects. We then used structural equation models (SEMs) to test and compare the mechanistic pathways of carbon allocation in natural versus planted forests.ResultsOur LMMs revealed a universal trade-off, with tree layer carbon density (TCD) strongly suppressing understory carbon density (UCD) (β = -0.22, P < 0.001) while synergistically promoting soil organic carbon density (SOCD) (β = 0.36, P < 0.001). SEM analysis (natural forests: CFI = 0.986, RMSEA = 0.064; planted forests: CFI = 0.960, RMSEA = 0.076) revealed divergent regulatory mechanisms. In natural forests, tree diversity directly buffered the suppressive effect of TCD on UCD via a significant positive path (β = 0.22, P < 0.01). This buffering pathway was absent in planted forests, leading to an amplified TCD-UCD trade-off (β = -0.54, P < 0.001).DiscussionOur findings demonstrate that forest carbon allocation is governed by a vertical trade-off and an above-belowground synergy, with tree diversity acting as a key modulator. Compared with complex natural forests, the carbon allocation mechanism in planted forests is simplified with more acute trade-offs. We conclude that enhancing structural and species diversity in plantations is a critical pathway for synergistically optimizing the entire ecosystem’s carbon sink capacity.

Tree species diversity is known to affect tree growth and leaf traits, which in turn can influence various ecosystem processes. However, the reported direction of these tree diversity effects is inconsistent, indicating that their outcomes depend strongly on ecological context. Using the long‐term Satakunta forest diversity experiment in Finland, we investigated how the effects of tree species diversity on growth and leaf traits vary with species identity, stand density, and spatial scale. By comparing the responses of light‐demanding Scots pine Pinus sylvestris and shade‐tolerant Norway spruce Picea abies , we show that the factors influencing diameter at breast height (DBH) and leaf traits differ between species with contrasting life‐history strategies. Pine needle terpene concentrations were lowest in neighbourhoods dominated by conspecifics, while spruce needle terpenes were unaffected by tree species composition. Increasing canopy cover reduced spruce dry needle mass but had no effect on the dry needle mass of pines. Likewise, the factors that influenced tree growth differed between species; spruce DBH was lowest in thinned stands but was unaffected by tree species composition, whereas pine DBH did not vary significantly with plot density but was reduced in neighbourhoods containing silver birch Betula pendula . Our findings also indicate that diversity effects on leaf traits primarily operate at the local scale, as statistical models assessing the effect of immediate neighbours on pine terpenes yielded significant results, whereas models assessing diversity effects on a plot‐level did not. In contrast, both pine and spruce DBH responded to plot and immediate‐neighbour level factors, implying that tree growth is influenced by broader stand‐level conditions, while leaf traits responses to diversity are more localised.

Wild bees are widely distributed and effective pollinators, yet they face significant threats such as degradation of forests. Forest restoration has been advocated as a strategy to mitigate these threats and stabilize biodiversity. However, there is a lack of understanding of the ecological consequences of forest restoration on bee diversity, particularly regarding interactions with tree diversity and microenvironment. Using data from the world's largest tree diversity experiment (BEF-China), this study examines how tree species richness, canopy cover, understorey vegetation, and microclimatic conditions affect bee diversity in the context of forest restoration. Our analysis of bee diversity data (8341 individuals from 79 species) revealed that these biotic factors had distinct effects on three dimensions of bee diversity. Specifically, canopy cover had a negative effect on bee taxonomic diversity but a positive effect on phylogenetic and functional diversity. However, these patterns were reversed when the cover of understorey vegetation was accounted for. Moreover, tree species richness exerted an indirect influence on bee diversity through understorey microenvironment. Our findings provide nuance into how tree species richness shapes bee communities via vegetation cover and microclimate, which is informative on habitat characteristics in forest restoration and conservation that better enable the safeguarding of pollinators.

ABSTRACT Aim Climate change poses a global threat to forest ecosystems. However, its effects are usually examined independently of local factors, assuming that functionally diverse forest habitat types within a single biome will react similarly. Here we evaluated how temperature influences the taxonomic and functional diversity of tree and shrub guilds, accounting for the regulatory effects of local factors across forest habitat types. Location Italy. Time Period From 1970 to 2020. Major Taxa Studied Trees and shrubs. Methods We integrated &gt; 5000 forest vegetation plots from a national databases with data on seven functional traits. We fitted regression models to quantify the individual and interaction effects of temperature, solar radiation (a proxy for topography), and soil moisture on the taxonomic and functional diversity of tree and shrub guilds across four main forest habitat types. Results Temperature gradients similarly affected the taxonomic and functional diversity of both tree and shrub guilds, although with a stronger magnitude for trees. Topographic solar radiation regulated mainly the temperature‐diversity relationship in trees, with a stronger positive effect on cold forest habitats compared to warm ones. Soil moisture exerted a stronger control on shrub guilds, especially in cold forest habitats, but with positive and negative effects on taxonomic and functional diversity, respectively. Assuming climate‐diversity responses will hold under climate change, projections to 2100 suggest that the diversity of warm forest habitats might reduce, possibly due to intensification of summer drought stress, while the diversity of cold forest habitats might increase as winter frost stress lessens. Main Conclusion Temperature is a strong biodiversity determinant. Still, projections should account for local regulatory mechanisms and consider that grouping different forest habitat types into a broad category can obscure critical diversity responses. The distinct responses of forest habitat types to topography‐mediated climate conditions suggest the need for targeted adaptive management strategies.

Tropical landscapes are undergoing rapid transformation due to human activities and global change. Forest restoration has emerged as a key strategy to mitigate biodiversity loss and climate warming. However, a standardized assessment of how different restoration methods contribute to biodiversity recovery and conservation remains lacking. Here, we present the first comprehensive comparison of tree diversity restoration and the drivers of recovery across five main reforestation methods (naturally regenerating forests, biodiverse restoration plantings, short- and long-rotation tree monocultures, agroforests) relative to three reference systems (agropastoral lands, degraded and conserved forest remnants). Tree inventories were conducted in 519 plots (900 m2 each) across two forest types (rainforest and seasonally dry forest) in the Atlantic forest of São Paulo state, Brazil, encompassing over 39,000 trees and 869 species. We found that: (1) all reforestation methods except short-rotation monoculture plots supported tree diversity recovery. In the rainforest, conserved remnant plots maintained the highest average Shannon diversity (Hill 1 = 29 ± 14), while naturally regenerating forests and restoration plantings approached the diversity of degraded remnant plots (15 ± 5). In seasonally dry forest, biodiverse restoration plantings and agroforests reached diversity levels comparable to conserved remnants (15 ± 6). Additionally, (2) recovery was influenced by forest age, climate (water availability), soil fertility, and landscape context, though the relative importance of these factors varied by method. Climate and landscape context were more influential for recovery in naturally regenerating forests, while soil conditions played a greater role in biodiverse restoration plantings. Lastly, (3) species composition in naturally regenerating forests most closely resembled that of conserved remnants. Conversely, restoration plantings and agroforests exhibited high compositional overlap across sites, reducing overall species richness. Our findings underscore the wide variation in biodiversity outcomes among and within reforestation methods, emphasizing that goals and strategies must align with local conditions to maximize benefits in complex tropical landscapes.

Long-term diversifying afforestation enhances soil microbial network complexity and stability.

Stand structural attributes exert stronger and scale-dependent control on forest biomass than tree diversity across typical forest ecosystems in China

Exploring the genetic diversity of monumental olive trees from southwestern Sicily

Changes in tree composition and diversity of streetscapes and their impact on allergenic risk of pollen during urban expansion: a case study in Chengdu, China

Sacred or religious forests are one of the most important but difficult to manage forest types due to high human interferences. The Swayambhu Religious Forest was selected for this study. This sacred forest was divided into three strata based on the stand age, considering the species composition, including established forests, generally comprising broadleaved species (old forests), emerging forests or young (10 years or above) forests, generally dominated by pine trees five years or above, and regeneration forest (newly established, less than five years of age, with a few scattered trees, by using the stratified systematic sampling method for data collection from 29 circular sample plots established in the forest. The Permutation-based ANOVA test showed significant variation in tree diversity and regeneration diversity among the three forest strata, but the Shannon diversity index was higher in the broadleaved forest in comparison to the regeneration and pine forests. The Spearman correlation analysis showed positive correlations in canopy density and Shannon diversity, tree diversity and regeneration diversity, and tree density and regeneration diversity of tree species, but there was no strong positive correlation between tree density and Shannon diversity. There was a negative correlation between canopy density and regeneration diversity, demanding canopy opening to promote natural regeneration of the forest. Both regeneration diversity and tree diversity were higher in the broadleaved forest, where anthropogenic disturbance was moderate, with 10 of the 14 tree species regenerating. The study showed a decline in richness of species diversity by age of forest.

Abstract Roadside green spaces (RGS) are an essential part of urban environments. These provide a variety of ecosystem services, including biodiversity conservation, carbon storage, and microclimate regulation. This study aims to assess RGS for tree diversity, carbon stock, and thermal comfort along four major roads of the Jawaharlal Nehru University campus, New Delhi. An extensive belt transect survey was employed with a total of 59 plots (10 m × 5 m each) covering a 5.5 km stretch of road. RGS supported 27 tree species from 27 genera and 15 families, comprising 19 native, 6 introduced and 2 invasive species. The diversity indices indicated low dominance (D = 0.16), moderate diversity (H′ = 2.47), and moderately high evenness (J′ = 0.75). The Fabaceae family was the most dominant, with Cassia fistula having the highest IVI. However, invasive species ( Leucaena leucocephala and Prosopis juliflora ) accounted for 47.17% of the individuals. Despite the abundance, these invasive species contributed minimally to carbon stock (0.59 and 0.23 tC/m 2 , respectively), underscoring that these are neither ecologically nor sustainably beneficial. Overall, the RGS stored 0.312 tC/m 2 of carbon. These also contributed to thermal comfort regulation, with on-field measurements showing reductions in air temperature by 0.80 to 2.24 °C and land surface temperature by 3.80 to 8.37 °C during April and May 2025. This research highlights the multifunctional role of RGS while emphasizing the urgent need to manage invasive species to secure their ecological and sustainability benefits. These findings confirm the role of RGS as an effective natural cooling system for megacities such as Delhi, which experiences intensifying heat waves and rising heat stress. For urban policy and planning, this underscores the need to integrate invasive species control and proactive RGS management into city-scale heat adaptation strategies.

Use of traditional medicines as an alternative to the conventional ones is gaining a lot of traction lately both globally and locally. Traditional Chinese Medicine is globally recognized for its long-standing use, and in Africa many communities embrace the practice as well. In Kenya the Maasai are in the forefront in matters traditional medicine, and it is known that the knowledge is specifically and purposefully passed on from senior citizens to the younger generation. This study intends to highlight the importance of the remaining urban forests and green spaces in conserving these important medicinal trees. It also informs and seeks to actuate traditional medicine knowledge conservation and retention for posterity. Eighteen species of trees were encountered in Oloolua forest of Kajiado county, following a stratified transect survey in the forests’ four distinct habitats. Of these, thirteen species belonging to twelve families were found to have documented ethno-medicinal significance and wide use amongst local and regional communities. The family that was most used was Celastraceae bearing two tree species. Data on ethno-medicinal significance was gotten after thorough online searches were conducted in research journals, Freefull PDF, Google scholar, ScienceDirect, and PubMed using keywords significant to the topic. The part of the trees most commonly used were the roots and bark, whereas decoction method of preparation was outrightly the most preferred. The ethno-medicine was found to be important in treatment and management of general pain, gastrointestinal disorders, respiratory, pulmonary, endocrinal illnesses, Malaria and other inflammation related disorders. A qualitative analysis of the acquired data grouped the illnesses into six illness categories with gastro-intestinal ranking highest at 28%. The harvesting of tree species to access roots and stems is a major concern as it threatens the very survival of these important tree species. Findings point out the critical role of urban forests in conserving ethnomedicinal tree diversity and sustaining indigenous knowledge systems.