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Removal of canopy trees by logging causes shifts in herbaceous diversity and increases invasibility of the forest understory. However, disturbed (cut) trees of many species do not die but resprout from remaining parts. Because sprouts develop vigorously immediately after disturbances, we hypothesized that sprouts of logged trees offset the changes in species richness and invasibility of the herbaceous layer by eliminating the rise in the resource availability during the time before regeneration from seeds develops. To test this, we analyzed data on herbaceous vegetation and sprout biomass collected in a broadleaved temperate forest in the Czech Republic before and for 6 years after logging. Sprouts that were produced by most of the stumps of logged trees offset large rises in species richness and cover of herbaceous plants and the resource availability that followed logging, but they affected the alien plants more significantly than the native plants. The sprouting canopy effectually eliminated most of the alien species that colonized the forest following a logging event. These findings indicate that in forests dominated by tree species with resprouting ability, sprouts drive the early post-disturbance dynamics of the herbaceous layer. By offsetting the post-disturbance vegetation shifts, resprouting supports forest resilience. [ABSTRACT FROM AUTHOR]

Host size and distance from an infected plant have been previously found to affect mistletoe occurrence in woody vegetation but the effect of host plant competition on mistletoe infection has not been empirically tested. For an individual tree, increasing competition from neighbouring trees decreases its resource availability, and resource availability is also known to affect the establishment of mistletoes on host trees. Therefore, competition is likely to affect mistletoe infection but evidence for such a mechanism is lacking. Based on this, we hypothesised that the probability of occurrence as well as the abundance of mistletoes on a tree would increase not only with increasing host size and decreasing distance from an infected tree but also with decreasing competition by neighbouring trees. Our hypothesis was tested using generalized linear models (GLMs) with data on Loranthus europaeus Jacq., one of the two most common mistletoes in Europe, on 1015 potential host stems collected in a large fully mapped plot in the Czech Republic. Because many trees were multi-stemmed, we ran the analyses for both individual stems and whole trees. We found that the probability of mistletoe occurrence on individual stems was affected mostly by stem size, whereas competition had the most important effects on the probability of mistletoe occurrence on whole trees as well as on mistletoe abundance. Therefore, we confirmed our hypothesis that competition among trees has a negative effect on mistletoe occurrence. [ABSTRACT FROM AUTHOR]

Resprouting multi-stemmed woody plants form an important component of the woody vegetation in many ecosystems, but a clear methodology for reliable measurement of their size and quick, non-destructive estimation of their woody biomass and carbon stock is lacking. Our goal was to find a minimum number of sprouts, i.e., the most easily obtainable, and sprout parameters that should be measured for accurate sprout biomass and carbon stock estimates. Using data for 5 common temperate woody species, we modelled carbon stock and sprout biomass as a function of an increasing number of sprouts in an interaction with different sprout parameters. The mean basal diameter of only two to five of the thickest sprouts and the basal diameter and DBH of the thickest sprouts per stump proved to be accurate estimators for the total sprout biomass of the individual resprouters and the populations of resprouters, respectively. Carbon stock estimates were strongly correlated with biomass estimates, but relative carbon content varied among species. Our study demonstrated that the size of the resprouters can be easily measured, and their biomass and carbon stock estimated; therefore, resprouters can be simply incorporated into studies of woody vegetation. [ABSTRACT FROM AUTHOR]

Abstract: We studied the effects of long-term fire exclusion on the structure and mortality of a caldén (Prosopis caldenia Burkart) woodland, a rare vegetation type remaining only in fragments in semi-arid Central Argentina. We tested the hypothesis that differences in caldén stand structure are consequence of differences in fire history by quantifying DBH and tree height in 30 plots set in caldén woodlands with fire occurring at least every 10 y, with fire excluded for 20–30 y and without fire for at least 60 y. Stem height, density and basal area increased after 20–30 years of fire exclusion. The frequently burned woodland had high mortality in all but the largest (>60 cm in DBH and >8 m in height) size class, whereas the fire-excluded plots exhibited high mortality only in the smallest stems (<15 cm in DBH and <3 m in height). Our results showed that the fire exclusion increased stem basal area and density while decreasing mortality of larger size classes and reducing resprouting of stems of any size; the probable explanation for these changes is a shift in the prevalent thinning mechanisms from fire-induced to competition-induced mortality. [Copyright &y& Elsevier]

Coppicing was widespread across Europe for many centuries, but during the last 150 years, it has been largely abandoned. Most of the former coppices have been converted to high forest, especially in Central and northwestern Europe. Recently, there has been renewed interest in restoring coppices in some regions, primarily for biomass production and nature conservation. However, there is limited information on the sprouting ability of European tree species, which is the key prerequisite for successful coppice restoration. To address this gap, we evaluated the post-harvest stump sprouting of the three main species of Central European coppices-sessile oak ( Quercus petraea (Mattuschka) Liebl.), European hornbeam ( Carpinus betulus L.) and small-leaved lime ( Tilia cordata Mill.)-in relation to the stump diameter and density of residual trees. Lime and hornbeam resprouted from stumps of all diameters, but sprouting ability declined with increasing stump diameter in sessile oak. Lime produced greater numbers of sprouts with greater diameters and heights than either oak or hornbeam. The number of sprouts per stump increased with stump diameter in all three species as did the height of lime and hornbeam sprouts, whereas there was no such effect on the height of oak sprouts. The sprouting of hornbeam and oak increased and decreased, respectively, with an increasing density of residual trees. In conclusion, our study shows that all of the studied species are able to resprout even at an old age and after a long period of neglect; however, there were important differences among the species. The results also indicate that the age of the parent trees at the time of cutting may significantly affect the tree species composition of a newly restored coppice. [ABSTRACT FROM AUTHOR]

An observed acceleration of tree mortality rates in European forests has been attributed to the impacts of climate change and extreme disturbances. Ecosystem recovery depends on regeneration success, but the recruitment of juveniles has been recognized as bottleneck in the development of forests. We investigated the potential importance of biotic (canopy tree abundance, ungulate herbivory) and abiotic (light, soil nutrients) factors in the limitation of regeneration in montane primary forests in central Europe. We used widely distributed forest inventory data (n = 348 plots) for two forest types, multiple tree taxa, and two life stages (seedlings and saplings). Seedling densities were promoted by more abundant parent trees, but saplings were either negatively influenced or unaffected by the number of conspecific adults. Browsing intensity (per capita defoliation severity) strongly limited the density of seedlings, but not saplings, at a community level. Low understory light levels were positively associated with seedling densities, but either did not affect or depressed sapling abundance A tolerance of shading was enhanced by nitrogen availability in some taxa. Our findings reflect highly complex, context‐specific regeneration processes that vary by species and life stage within species. [ABSTRACT FROM AUTHOR]

Managing forests to sustain their diversity and functioning is a major challenge in a changing world. Despite the key role of understory vegetation in driving forest biodiversity, regeneration and functioning, few studies address the functional dimensions of understory vegetation response to silvicultural management.We assessed the influence of the silvicultural regimes on the functional diversity and redundancy of European forest understory. We gathered vascular plant abundance data from more than 2000 plots in European forests, each associated with one out of the five most widespread silvicultural regimes. We used generalized linear mixed models to assess the effect of different silvicultural regimes on understory functional diversity (Rao's quadratic entropy) and functional redundancy, while accounting for climate and soil conditions, and explored the reciprocal relationship between three diversity components (functional diversity, redundancy and dominance) across silvicultural regimes through a ternary diversity diagram.Intensive silvicultural regimes are associated with a decrease in functional diversity and an increase in functional redundancy, compared with unmanaged conditions. This means that although intensive management may buffer communities' functions against species or functional losses, it also limits the range of understory response to environmental changes.Policy implications. Different silvicultural regimes influence different facets of understory functional features. While unmanaged forests can be used as a reference to design silvicultural practices in compliance with biodiversity conservation targets, different silvicultural options should be balanced at landscape scale to sustain the multiple forest functions that human societies are increasingly demanding. [ABSTRACT FROM AUTHOR]

Knowledge of the quantity of woody biomass of poplar short-rotation coppice (SRC) on agricultural land is a basic tool for management decisions like rotation length, volume production and the financial balance sheet of economic activities. The expansion of SRC requires a fast, reliable, easily applicable and cheap method for estimating the biomass yield, but existing methods are based on labour-demanding and lengthy measurements of all shoots per tree. The objective of this study was to verify a novel rapid biomass estimation method that uses averaged attributes of only a few largest shoots as a predictor variable for woody biomass in a poplar SRC, hybrid clone J-105 (Populus nigra × P. maximowiczii). Using data from 39 sample stumps with 187 shoots in total, we modelled shoot biomass as a function of an increasing number of shoots in interaction with different shoot parameters at two poplar SRC plantations. Results showed that the DBH of only three of the largest shoots per stump proved to be accurate estimators of the total shoot biomass of the individual stump. Comparison of biomass estimates at the stand level with a real amount of biomass indicated differences between 6-14%, depending on the site. [ABSTRACT FROM AUTHOR]

African tropical forests are recognised for their important contributions to biodiversity conservation and carbon storage, yet they remain notably understudied. Understanding how current climatic conditions regulate species composition and diversity is crucial for predicting the resilience of these ecosystems in an era of global change. This study examines biodiversity patterns and the conservation status of species among disjunct forest communities in wet, moist and dry forest zones of Ghana, West Africa. Detailed forest inventory data were collected to assess community composition and tree diversity metrics. We analysed how climatic factors influenced variations in tree diversity and the occurrence of at-risk species. A total of 3471 trees representing 242 species were surveyed, with 17.4 % classified as threatened or near-threatened according to global extinction risk assessments. Tree diversity declined significantly from wet to dry forest communities. We found that vapour pressure deficit (VPD) negatively affected community diversity potential across the study area. However, we also detected evidence for potential mitigation of VPD impacts by greater soil moisture storage, leading to stable biodiversity levels in more mesic soil environments. At-risk species were more common in high-rainfall regions relative to drier environments. However, across the study area, the number of at-risk species increased with the combined effects of high VPD and low soil moisture. This study highlights the distinct roles of VPD and soil water storage in maintaining tropical forest tree diversity, with important implications for ecosystem stability in a changing climate. • Unique species were found in the wet, moist and dry forests of Ghana. • The wet forest serves as a biodiversity hotspot with over 100 tree species per hectare. • The highest proportion of threatened species was observed in the wet forest. • Vapour pressure deficit and soil moisture shape species composition and diversity. • Soil phosphorus, calcium, and nitrogen explained significant variation in species composition. [ABSTRACT FROM AUTHOR]

Aim: Natural disturbances influence forest structure, successional dynamics and consequently, the distribution of species through time and space. We quantified the long‐term impacts of natural disturbances on lichen species richness and composition in primary mountain forests, with a particular focus on the occurrence of endangered species. Location: Ten primary mountain spruce forest stands across five mountain chains of the Western Carpathians, a European hotspot of biodiversity. Methods: Living trees, snags and downed logs were surveyed for epiphytic and epixylic lichens in 57 plots. Using reconstructed disturbance history, we tested how lichen species richness and composition was affected by the current forest structure and disturbance regimes in the past 250 years. We also examined differences in community composition among discrete microhabitats. Results: Dead standing trees as biological legacies of natural disturbances promoted lichen species richness and the occurrence of threatened species at the plot scale, suggesting improved growing conditions for rare and common lichens during the early stages of recovery post disturbance. However, high‐severity disturbances compromised plot‐scale species richness. Both species richness and the number of old‐growth specialists increased with time since disturbance (i.e., long‐term uninterrupted succession). No lichen species was strictly dependent on live trees as a habitat, but numerous species showed specificity to logs, standing objects or an admixture of tree species. Conclusions: Lichen species richness was lower in regenerating, young and uniform plots compared with overmature and recently disturbed areas. Natural forest dynamics and its legacies are critical to the diversity and species composition of lichens. Spatio‐temporal consequences of natural dynamics require a sufficient area of protected forests for provisioning continual habitat variability at the landscape scale. Ongoing climatic changes may further accentuate this necessity. Hence, we highlighted the need to protect the last remaining primary forests to ensure the survival of regionally unique species pools of lichens. [ABSTRACT FROM AUTHOR]

The expected future intensification of forest disturbance as a consequence of ongoing anthropogenic climate change highlights the urgent need to more robustly quantify associated biotic responses. Saproxylic beetles are a diverse group of forest invertebrates representing a major component of biodiversity that is associated with the decomposition and cycling of wood nutrients and carbon in forest ecosystems. Disturbance-induced declines or shifts in their diversity indicate the loss of key ecological and/or morphological species traits that could change ecosystem functioning. Functional and phylogenetic diversity of biological communities is commonly used to link species communities to ecosystem functions. However, our knowledge on how disturbance intensity alters functional and phylogenetic diversity of saproxylic beetles is incomplete. Here, we analyzed the main drivers of saproxylic beetle abundance and diversity using a comprehensive dataset from montane primary forests in Europe. We investigated cascading relationships between 250 years of historical disturbance mechanisms, forest structural attributes and the taxonomic, phylogenetic and functional diversity of present-day beetle communities. Our analyses revealed that historical disturbances have significant effects on current beetle communities. Contrary to our expectations, different aspects of beetle communities, that is, abundance, taxonomic, phylogenetic and functional diversity, responded to different disturbance regime components. Past disturbance frequency was the most important component influencing saproxylic beetle communities and habitat via multiple temporal and spatial pathways. The quantity of deadwood and its diameter positively influenced saproxylic beetle abundance and functional diversity, whereas phylogenetic diversity was positively influenced by canopy openness. Analyzing historical disturbances, we observed that current beetle diversity is far from static, such that the importance of various drivers might change during further successional development. Only forest landscapes that are large enough to allow for the full range of temporal and spatial patterns of disturbances and post-disturbance development will enable long-term species coexistence and their associated ecosystem functions. [ABSTRACT FROM AUTHOR]

• Major tree species of the Czech Republic experienced drought-induced growth reduction. • Drought impacts on growth trends and drought resistance are species-specific. • Drought impacts were more pronounced on trees at lower elevations. • Higher drought intensity regulates the impacts of tree age and elevation on drought resistance. In recent decades, extreme droughts have affected Central Europe, altering forest structure and function with significant socioeconomic consequences. Most Central European forests are used for timber production and provide various ecosystem services and habitats for forest-dwelling species. The extent to which recent weather extremes have impacted these forests was poorly quantified. Furthermore, the drivers of drought resistance remain uncertain, potentially misleading predictions of future forest development. In this study, we analyzed the impacts of recent droughts on the growth of managed forests in the Czech Republic based on tree-ring width of five common and commercially important tree species, European beech (Fagus sylvatica), Norway spruce (Picea abies), Scots pine (Pinus sylvestris), sessile oak (Quercus petraea), and pedunculate oak (Quercus robur). We assessed the 2015–2019 "dry period", which contains two extreme droughts. We also examined the drivers of growth reductions during three major drought events (2003, 2015, 2018) between 1995 and 2019, including the effects of tree age, size, elevation, and drought intensity. We identified drought-induced growth reductions for all five species during the "dry period" compared with the 2005–2009 "reference period", and Scots pine exhibited the highest resistance to drought (-13% growth) whereas Norway spruce showed the highest drought sensitivity (-30% growth). However, for the two recent droughts, the resistance of the three broadleaved species was higher than the two coniferous species. The effects of age and elevation on drought resistance varied with drought intensity. And European beech trees at lower elevations were significantly more negatively affected by droughts than trees at higher elevations. Our results indicate that a highly variable growth response to drought across species can be expected as climate changes. Under warmer and drier conditions, growth reductions could be more pronounced for drought-sensitive species at lower elevations, potentially threatening timber supply sustainability and other services. [ABSTRACT FROM AUTHOR]

• The impacts of logging were investigated using LiDAR and observed microclimate data. • The understory of logged tropical forests was 1.5 °C warmer than unlogged forests. • Logging undermined the capacity of forests to buffer temperature in extreme warmdays. Selective logging is responsible for approximately 50 % of human-induced disturbances in tropical forests. The magnitude of disturbances from logging on the structure of forests varies widely and is associated with a multitude of impacts on the forest microclimate. However, it is still unclear how changes in the spatial arrangement of vegetation arising from selective logging affect the capacity of forests to buffer large-scale climate (i.e., macroclimate) variability. In this study, we leveraged hundreds of terrestrial LiDAR measurements across tropical forests in Malaysian Borneoto quantify the impacts of logging on canopy structural traits, using a space-for-time approach. This information was combined with locally measured microclimate temperatures of the forest understory to evaluate how logging disturbances alter the capacity of tropical forests to buffer macroclimate variability. We found that heavily logged forests were approximately 12 m shorter and had 65 % lower plant area density than unlogged forests, with most plant material allocated in the first 10 m above ground. Heavily logged forests were on average 1.5 °C warmer than unlogged forests. More strikingly, we show that subtle changes in the forest structure were sufficient to reduce the cooling capacity of forests during extremely warm days (e.g., anomalies > 2σ), while understory temperatures in heavily logged forests were often warmer than the macroclimate under the same conditions. Our results thus demonstrate that selective logging is associated with substantial changes in the fine-scale thermal regime of the understory. Hence, mitigating and managing logging disturbances will be critical for maintaining niches and thermal limits within tropical forests in the future. [Display omitted] [ABSTRACT FROM AUTHOR]

Establishing a better understanding of changes in mistletoe abundance over time could prove useful in the development of future conservation and management strategies for mistletoe-host complexes. The purpose of this study was to describe and examine how time influenced host trees sessile oak (Quercus petraea (Matt) Liebl.) and the abundance dynamics of their hemiparasites yellow mistletoe (Loranthus europaeus Jacq.). The research was conducted in Podyjí National Park, Czech Republic, from 2011–2015. Each oak stem (1599) was visually checked for the presence of he- miparasites during the bud growth period. We investigated the temporal dynamics of L. europaeus abundance (number of L. europaeus shrubs per Q. petraea stem) and volume (total volume of L. europaeus shrubs per stem) on individual host stems using linear mixed effects models. The abundance of L. europaeus increased with larger host diameter at breast height (DBH), time and their interaction. The abundance of L. europaeus slightly increased over time on hosts with smaller DBH, but this phenomenon slowed down as host DBH increased. Mistletoe abundance started decreasing over time on hosts with large DBH. The study showed that time plays an important role in determining the distribution of mistletoes in the stand. Thanks to the inclusion of the time component, it was possible to create a model that showed the most vulnerable groups of host trees to which forest management should focus on. [ABSTRACT FROM AUTHOR]

Abandonment of coppicing is one of the main reasons of diversity decline in European temperate forests. To reverse this trend, coppicing has been reintroduced in several forests, especially in areas of high conservation value. However, empirical information on the effects of coppicing on plant diversity and composition is still scarce. By comparing vegetation data from active coppices and beech-dominated high forests in the Banat region in Romania, we tested the hypothesis that coppices have a higher plant diversity and different plant species composition than high forests. Data were collected in 60 randomly placed phytosociological relevés and were analysed using linear models and multivariate methods. As expected, we found differences in understorey plant composition. Herb species with various environmental demands-sciophytes-(hemi)-heliophytes and grassland species-were more frequent in coppices whereas high forests had more vernal species and sciophytes. Coppices also had slightly greater plant diversity but did not differ in herb species richness. Our results demonstrate that coppicing has a small positive effect on plant diversity but a large effect on species composition. Coppice restoration may be especially beneficial for populations of thermophilous and non-forest species. [ABSTRACT FROM AUTHOR]

The decrease in canopy openness after the abandonment of traditional coppicing in the twentieth century has been previously identified as the main reason behind changes in species composition and diversity in lowland woodlands in Europe. However, little is known about the role of other traditional practices in shaping woody vegetation and canopy cover in the past. In a traditionally managed landscape of the Banat region, western Romania, where long-established activities, such as human-induced burning, coppicing and grazing of woody vegetation are still being practised, we studied woody vegetation structure and canopy openness in 70 plots. Using a set of structural traits, we classified woody vegetation into four groups: active coppices, scrubs, abandoned coppices and high forests. Surprisingly, the lowest canopy openness was found in active coppices, probably due to high canopy recovery rate and selection coppice system. Scrubs, in which grazing and browsing were the most common activities in the past, were the most open type of woody vegetation. Our results emphasize the role of other traditional management practices in addition to coppicing in keeping canopy openness relatively high and spatially heterogeneous. [ABSTRACT FROM AUTHOR]

Most experimental evidence on the relationship between biodiversity and ecosystem functioning comes from ecosystems with fast-growing plants, such as grasslands. Although forests provide essential ecological services, they have been less well investigated., We used dendrochronology to compare the tree radial growth rates of four important timber species in replicated, spatially mapped stands that differed in tree composition and diversity within a central European managed forest., Growth rates differed among species but were largely unaffected by the density of neighbouring trees., Increasing stand diversity enhanced individual growth rates, after accounting for the effects of tree density and size. These increases were statistically indistinguishable among the four species. In contrast, the effects of stand and neighbourhood species composition on growth rates were non-significant., Policy implications. Our study of long-established central European forest stands revealed levels of tree diversity can be increased in managed forests, with the potential for modest increases in tree growth rates. These results suggest that in addition to the biodiversity and risk mitigation benefits associated with shifting practices away from monoculture management, increased carbon sequestration and yields in mature forests are likely to be realized. Our results suggest that it is possible to increase forest diversity with little or no costs to production and even with the potential for modest increases in tree growth rates. [ABSTRACT FROM AUTHOR]

Understory herbs and soil invertebrates play key roles in soil formation and nutrient cycling in forests. Studies suggest that diversity in the canopy and in the understory are positively associated, but these studies often confound the effects of tree species diversity with those of tree species identity and abiotic conditions. We combined extensive field sampling with structural equation modeling to evaluate the simultaneous effects of tree diversity on the species diversity of understory herbs, beetles, and earthworms. The diversity of earthworms and saproxylic beetles was directly and positively associated with tree diversity, presumably because species of both these taxa specialize on certain species of trees. Tree identity also strongly affected diversity in the understory, especially for herbs, likely as a result of interspecific differences in canopy light transmittance or litter decomposition rates. Our results suggest that changes in forest management will disproportionately affect certain understory taxa. For instance, changes in canopy diversity will affect the diversity of earthworms and saproxylic beetles more than changes in tree species composition, whereas the converse would be expected for understory herbs and detritivorous beetles. We conclude that the effects of tree diversity on understory taxa can vary from positive to negative and may affect biogeochemical cycling in temperate forests. Thus, maintaining high diversity in temperate forests can promote the diversity of multiple taxa in the understory. [ABSTRACT FROM AUTHOR]

Dracaena cinnabari , the dominant endemic tree of Socotra Island (Yemen), is in serious decline. The effect this will have on the island's plant diversity remains unknown. We aimed to identify plants associated with Dracaena understorey and assess the importance of Dracaena for maintaining plant diversity. A total of 272 relevés were sampled in Dracaena understorey and in open sites to record the number of individuals of vascular plants. Species richness and composition were compared between understorey and open sites, and species associated with each of these habitats were identified. Additionally, the effect of canopy closure on species richness and abundance was analysed. We also recorded woody species composition of Dracaena stands and investigated spatial relations between Dracaena and other mature woody plants. Understorey plant species composition differed from open site composition. The former habitat showed higher β-diversity and species richness. Among recorded plants, 15 species were classified as understorey specialists, 6 as open-site specialists, and 23 as generalists. Rare species, especially endemics, were more common in the understorey. Canopy closure had differential effect on species abundances among the species classes. Species richness and total abundance were found to be highest in the understorey, particularly in the case of low-to-intermediate canopy closure where understorey and open-site specialists may co-occur. For mature woody plant species, Dracaena was spatially independent from other woody species at most distances. Our results suggest that the decline of Dracaena may negatively affect plant diversity, reduce abundance of rare endemic plants and lead to homogenization of vegetation. As no other tree species exists in the study area which could replace the Dracaena , our findings underline the importance of conservation efforts to preserve Dracaena stands on Socotra. [ABSTRACT FROM AUTHOR]