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In the managed beech forests of Central Italy (Molise), the diversity of saproxylic species is potentially under threat by intensive management. To evaluate the impact of forestry on the biodiversity of these ecosystems, we analyzed the relationship between abundance of saproxylic beetles and (i) forest stand exposure and elevation, (ii) deadwood availability (coarse woody debris - CWD - and stumps), (iii) abundance of microhabitats. Four sampling sectors with different altitudes and exposure were identified in a 400-ha study area in the Appenine mountains. Fifteen circular plots (13 m radius) were established in each sector where deadwood and microhabitats were surveyed and saproxylic beetles sampled. We fitted joint species distribution models to quantify the relationship between forest attributes and saproxylic species’ abundance, including the interactions with their family and trophic category. Overall, 2334 specimens belonging to 64 species of saproxylic beetles were collected. Both abundance and species richness were higher in the sectors with high elevation (respectively, 55% and 44%) and South exposure (respectively, 28% and 44%). Average deadwood volumes were low (stumps: 7.6 m3 ha-1; CWD: 0.3 m3 ha-1; snags: 0.4 m3 ha-1), and insect galleries were the most abundant microhabitat (380 records over a total of 434). The most important variables affecting abundance were stump characteristics (model deviance = 81.2), elevation (deviance = 64.7), and CWD characteristics (deviance = 58.0). Our results show that topographical variables and forest structure jointly affect the abundance patterns of saproxylic beetle communities in managed beech forests. These ecological interactions imply that management has different impacts on the saproxylic communities in different topographic conditions. To acknowledge this complexity we advocate for a landscape-level forest management supporting the local beetle diversity maintaining a mosaic of semi-natural forest characteristics in different topographic contexts. The ecological value of the forest landscape will be further enhanced by the application of closer-to-nature management interventions based on deadwood retention, microhabitat creation and tree retention, in line with the guidelines of the new EU Forest Strategy for 2030.

The creation of artificial snags, so-called high stumps, within forest management operations is a recently established tool to enrich standing deadwood as a habitat for saproxylic species. In this study, we analysed the impact of active high stump management on saproxylic beetle species. We selected 63 high stumps in six Bavarian forest districts (Germany), which were felled and subjected to close examination, focusing on beetle (Coleoptera) colonization. We identified 63 emerged coleopteran species belonging to 29 families; a further 10 taxa were identified only at the genus or family level, respectively. Moreover, 17% of the obtained taxa are listed in the German Red List of Coleoptera. Furthermore, 32% of the examined high stump trunks, predominantly broad-leaved tree species, harboured Red List beetle taxa. In particular, trembling aspen (Populus tremula) showed a disproportionately high number of Red List beetle species. The total species richness of beetles was independent of the height, diameter and decay stage of the snags. High stumps (snags) containing Red List beetle species tended to have higher amounts of deadwood in their surroundings, but the difference was not significant. According to the results of our study, actively creating high stumps proved to be a suitable method for creating habitats and serve as stepping-stones for endangered saproxylic species. Proactive high stump management during harvest can be a valuable component of deadwood management and biodiversity protection in forests.

Abstract Functional trait approaches are common in ecology, but a lack of clear hypotheses on how traits relate to environmental gradients (i.e., trait–niche relationships) often makes uncovering mechanisms difficult. Furthermore, measures of community functional structure differ in their implications, yet inferences are seldom compared among metrics. Community‐weighted mean trait values (CWMs), a common measure, are largely driven by the most common species and thus do not reflect community‐wide trait–niche relationships per se. Alternatively, trait–niche relationships can be estimated across a larger group of species using hierarchical joint species distribution models (JSDMs), quantified by a parameter Γ. We investigated how inferences about trait–niche relationships are affected by the choice of metric. Using deadwood‐dependent (saproxylic) beetles in fragmented Finnish forests, we followed a protocol for investigating trait–niche relationships by (1) identifying environmental filters (climate, forest age, and deadwood volume), (2) relating these to an ecological function (dispersal ability), and (3) identifying traits related to this function (wing morphology). We tested 18 hypothesized dispersal relationships using both CWM and Γ estimates across these environmental gradients. CWMs were more likely than Γ to show support for trait–niche relationships. Up to 13% of species' realized niches were explained by dispersal traits, but the directions of effects were consistent with fewer than 11%–39% of our 18 trait–niche hypotheses (depending on the metric used). This highlights the difficulty in connecting morphological traits and ecological functions in insects, despite the clear conceptual link between landscape connectivity and flight‐related traits. Caution is thus warranted in hypothesis development, particularly where apparent trait–function links are less clear. Inferences differ when CWMs versus Γ estimates are used, necessitating the choice of a metric that reflects study questions. CWMs help explain the effects of environmental gradients on community trait composition, whereas the effects of traits on species' niches are better estimated using hierarchical JSDMs.

Most European forests are used for timber production. Given the limited extent of unmanaged (and especially primary) forests, it is essential to include commercial forests in the conservation of forest biodiversity. In order to develop ecologically sustainable forest management practices, it is important to understand the management impacts on forest-dwelling organisms. Experiments allow testing the effects of alternative management strategies, and monitoring of multiple taxa informs us on the response range across forest-dwelling organisms. To provide a representative picture of the currently available information, metadata on 28 multi-taxa forest management experiments were collected from 14 European countries. We demonstrate the potential of compiling these experiments in a single network to upscale results from the local to continental level and indicate directions for future research. Among the different forest types, temperate deciduous beech and oak-dominated forests are the best represented in the multi-taxa management experiments. Of all the experimental treatments, innovative ways of traditional management techniques (e.g., gap cutting and thinning) and conservation-oriented interventions (e.g., microhabitat enrichment) provide the best opportunity for large-scale analyses. Regarding the organism groups, woody regeneration, herbs, fungi, beetles, bryophytes, birds and lichens offer the largest potential for addressing management–biodiversity relationships at the European level. We identified knowledge gaps regarding boreal, hemiboreal and broadleaved evergreen forests, the treatments of large herbivore exclusion, prescribed burning and forest floor or water manipulations, and the monitoring of soil-dwelling organisms and some vertebrate classes, e.g., amphibians, reptiles and mammals. To improve multi-site comparisons, design of future experiments should be fitted to the set-up of the ongoing projects and standardised biodiversity sampling is suggested. However, the network described here opens the way to learn lessons on the impact on forest biodiversity of different management techniques at the continental level, and thus, supports biodiversity conservation in managed forests.

After large and severe wildfires, the establishment of tree regeneration, particularly for species without specific fire-adaptive traits, can be challenging. Within harsh environments, the presence of favorable microsites, as those provided by deadwood, enhancing microclimatic conditions, is crucial to the re-establishment of forest cover and thus to foster recovery dynamics. Active restoration strategies can have an impact on these dynamics, altering or hindering them. The main hypothesis of this study is that manipulating deadwood in terms of quantity and spatial arrangement can result in differences in natural regeneration density and composition. Post-disturbance regeneration dynamics and the role played by deadwood over time in the creation of safe sites for seedling establishment were investigated in an area affected by a high-severity wildfire that underwent different post-fire restoration treatments along a gradient of increasing deadwood manipulation, spanning from salvage logging to non-intervention. Two inventories were performed 5 and 11 years after the fire. Ground cover proportion was significantly different among treatments, with lower values of lying deadwood in salvaged sites. A higher probability of regeneration establishment close to deadwood was found in both surveys, confirming the facilitating role of deadwood on post-fire forest regeneration. Microsite dynamics resulting from deadwood facilitation were highlighted, with establishment probability and anisotropic relationships between deadwood elements and seedlings changing over time, as recovery processes slowly improved environmental conditions. In dry mountain areas affected by stand-replacing wildfires, by removing deadwood, salvage logging reduces the number of safe sites for regeneration, further impairing the ecosystem recovery. Passive management should be the ecologically preferred management strategy in these conditions, although intermediate interventions (e.g., felling without delimbing, leaving deadwood on the ground) could be effective alternatives, accelerating snag fall dynamics and immediately increasing favorable microsite availability. [ABSTRACT FROM AUTHOR]

Selective browsing by deer on young trees may impede the management goal of increasing forest resilience against climate change and other disturbances. Deer population density is often considered the main driver of browsing impacts on young trees, however, a range of other variables such as food availability also affect this relationship. In this study, we use browsing survey data from 135 research plots to explore patterns of roe deer (Capreolus capreolus) browsing pressure on woody plants in mountainous forests in central Europe. We fitted species‐specific generalised linear mixed models for eight woody taxa, assessing the potential effects of understory characteristics, roe deer abundance and lying deadwood on browsing intensity. Our study reveals conspecific and associational effects for woody taxa that are intermediately browsed by roe deer. Selective browsing pressure was mediated by preferences of plants, in that, browsing of strongly preferred woody taxa as for example mountain ash (Sorbus aucuparia) and of least preferred woody taxa, for example Norway spruce (Picea abies) was not affected by the surrounding understory vegetation, while browsing pressure on intermediately browsed species like for example silver fir (Abies alba) was affected by understory characteristics. Contrary to our expectations, roe deer abundance was only positively associated with browsing pressure on silver fir and bilberry (Vaccinium myrtillus), while all other plants were unaffected by deer abundance. Finally, we did not find an influence of lying deadwood volume on the browsing pressure on any woody‐plant species. Overall, our results indicate that patterns in browsing preference and intensity are species‐specific processes and are partly affected by the surrounding understory vegetation. Current management strategies that aim to reduce browsing pressure through culling may be inefficient as they do not address other drivers of browsing pressure. However, managers also need to consider the characteristics of the local understory vegetation in addition to deer abundance and design species‐specific plans to reduce browsing on woody plant taxa. [ABSTRACT FROM AUTHOR]

Habitat loss is considered a major threat for biodiversity. However, the scales on which its effects occur are still insufficiently understood, namely, is the amount of available habitat important for species richness on both local and landscape scales? We studied the effects of local and landscape‐scale habitat amount on local‐scale species density of deadwood‐dependent lichens in Swedish boreal forests. Creation and retention of deadwood are common practices to benefit forest biodiversity, and recognizing the relevant scale is critical for them to be successful.We surveyed deadwood‐dependent lichens in 90 unmanaged forest stands that differed in the local and landscape habitat amount. The local habitat amount was measured as the amount of deadwood in the sampled stands (m2 deadwood ha−1), while six alternative proxies were used to estimate the landscape habitat amount, that is, the amount of deadwood in the surrounding landscapes. Lichen species density (number of species per standardized deadwood area of 3.7 m2) was modelled as a function of local and landscape habitat amount at multiple scales (300 m–5 km from the stands).Lichen species density increased with the landscape habitat amount. The proportion of old forests (>100 years, including newly clear‐cut stands that until recently were old forests) within 5 km from the stands explained species density better than the other proxies of landscape habitat amount. Local deadwood amount did not affect species density, and there was no interaction between the local and landscape habitat amount.Synthesis and applications: To promote the conservation of deadwood‐dependent lichens, the amount of old forests in managed forest landscapes should be maintained or increased. A certain amount of deadwood hosted more lichen species when situated in a landscape with more old forest, while there was no effect of the local deadwood amount. This suggests that management aimed at increasing the local species density of deadwood‐dwelling lichens should focus on creating and maintaining habitat in the surrounding landscape rather than only adding deadwood to that local site. In other words, effective management for deadwood‐dependent lichen diversity requires landscape‐scale habitat protection. [ABSTRACT FROM AUTHOR]

Antrodiella species (Agaricomycotina, Polyporales) are often growing on or near to the living, dead, or dying fruitbodies of pioneer wood-inhabiting fungi. Antrodiella citrinella always occurs on wood that previously has been decayed by the polypore Fomitopsis pinicola. However, the underlying mechanism remained unclear. Based on field observations, it has been assumed that the succeeding species is not only a highly competitive wood decomposer but also a mycoparasite feeding on the preceding species. To investigate the interaction between A. citrinella and the putative host F. pinicola, the species were grown in dual cultures at different temperatures (5–25 °C). The interaction tests were complemented with qualitative enzymatic tests for both species and microscopic examination of the interaction zone. In the dual cultures, A. citrinella replaced F. pinicola only at low temperature (5 °C); at higher temperatures (25 °C), it was vice versa. Light microscopy revealed preferential growth of A. citrinella toward F. pinicola, hyphal contact, and finally death of F. pinicola hyphae. Enzymatic tests showed that A. citrinella is capable to degrade extracellular proteins, chitin, cellulose, and lignin. We interpret the interaction as mycoparasitism, as we suggest that A. citrinella is capable to recognize, kill, and feed from F. pinicola, beside its ability to degrade woody substrates. The results are discussed in an ecological context. [ABSTRACT FROM AUTHOR]

Scapania apiculata, Scapania carinthiaca, and Scapania scapanioides are rare deadwood-dwelling liverworts threatened across Europe. Scapania carinthiaca is thus listed in the Habitats Directive. However, their distribution data are scattered, and their ecologic demands are insufficiently studied. Here, we present new locations and data on the ecology of the species, which resulted from a targeted search in selected regions of Austria. We found ten new sites each for Scapania apiculata and Scapania scapanioides and twenty for Scapania carinthiaca. Reproduction was exclusively asexual. The macroclimates of all known locations in Austria did not differ significantly between the three species. It was consistently wet, with a mean annual precipitation of 1615.3 mm, a high evenness of rainfall, and a low desiccation risk. The mean temperature averaged 7.4 °C. The habitat was shaded dead wood of Picea abies, Abies alba, and Fagus sylvatica of all decay stages at a median distance of 2.5 m from streams or springy areas in semi-natural forests of montane and submontane regions. Thus, high deadwood volumes under a suitable climate are a prerequisite for the occurrences of the species. The number of locations of new finds has more than doubled in Austria and thus in Europe. [ABSTRACT FROM AUTHOR]

Aim: The biogeography of European forests presents many interesting case studies, as inferred from phylogeography, contemporary population genetics, and distribution modelling of saproxylic species. Here, we pose four main hypotheses: (i) the phylogeographic paradigm known for temperate species in Europe is also applicable for saproxylic taxa; (ii) current expansion is occurring only in some genetic lineages; (iii) genetic diversity decreases from east to west, reflecting differences in forest naturalness and management; and (iv) climatic changes will force a northward range shift. Location: Europe. Taxon: The saproxylic beetle, Cucujus cinnaberinus (Scopoli, 1763). Methods: Beetles from 37 locations throughout the species range were genotyped using microsatellites and mtDNA (468 and 237 individuals, respectively). Molecular data were analysed to describe population diversity, structure, and demography. 200 records were used to model distribution based on climate data. Results: mtDNA analyses revealed three clades: the most divergent in Italy and two less distinct in north‐western and central‐to‐southeastern Europe. Microsatellites showed no clear geographic distribution pattern except for a distinct lineage in Italy. The highest genetic diversity was found in southern refugia, in natural forests of Central‐Eastern Europe, and in a mixing zone in Pannonia. During the Holocene, the Italian population declined, whereas populations in the rest of Europe showed no clear changes. Distribution models revealed the existence of glacial refugia along the coasts of the Adriatic and Black Seas, and northward dispersal in the Holocene continued in the XXI century. Conclusions: C. cinnaberinus has a complex historical biogeography, discordant with patterns known for temperate or boreal taxa. The current expansion occurs only in populations from mainland Europe, whereas southernmost populations are in decline. Current genetic diversity is shaped by recent forest management, which is the least intensive in Eastern Europe. Climate change will most likely enhance northward dispersal and threaten the survival of the southernmost populations. [ABSTRACT FROM AUTHOR]

The species‐energy hypothesis predicts increasing biodiversity with increasing energy in ecosystems. Proxies for energy availability are often grouped into ambient energy (i.e., solar radiation) and substrate energy (i.e., non‐structural carbohydrates or nutritional content). The relative importance of substrate energy is thought to decrease with increasing trophic level from primary consumers to predators, with reciprocal effects of ambient energy. Yet, empirical tests are lacking. We compiled data on 332,557 deadwood‐inhabiting beetles of 901 species reared from wood of 49 tree species across Europe. Using host‐phylogeny‐controlled models, we show that the relative importance of substrate energy versus ambient energy decreases with increasing trophic levels: the diversity of zoophagous and mycetophagous beetles was determined by ambient energy, while non‐structural carbohydrate content in woody tissues determined that of xylophagous beetles. Our study thus overall supports the species‐energy hypothesis and specifies that the relative importance of ambient temperature increases with increasing trophic level with opposite effects for substrate energy. [ABSTRACT FROM AUTHOR]

Deadwood is one of the main structural features of forest ecosystems and plays an important role in the nutrient cycle, in maintaining production and environmental heterogeneity, and acts as an indicator for assessing the biodiversity of forest ecosystems. This research was conducted with the aim of evaluating the quantitative and qualitative characteristics of deadwood according to the influence of forest accessibility indicators in a comparison between natural and recreational forests. The studied area was divided into three accessibility classes based on the slope gradient range, the slope direction towards the nearest road, the road type, and distance from the road. These classes were: Easy-recreational forest (RE-F), Medium-natural forest 1 (NA-F1), and Difficult-natural forest 2 (NA-F2). In each accessibility class, three transects (750 × 50 m) were established, and three deadwood groups (snag, log, and stump) were recorded along the transects and their volume was calculated. The results of the analysis of variance show that accessibility has a significant effect on the presence of deadwood. The number and volume of snags, logs and dead stumps per hectare was higher in NA-F2 than in NA-F1 and RE-F. In each of the investigated classes, logs and stumps had the highest and the lowest number and volume of deadwood per hectare, respectively. The snag longevity index (= log volume/snag volume) decreased with accessibility. NA F2 showed the greatest value, while REF and NA F1 were not significantly different from each other. The results show that decay classes DC2 in NA-F2 and DC3 in NA-F1 and RE-F had the highest percentage of decay frequency. Finally, the forest accessibility indicators have a significant effect on the quantity, quality and distribution of different groups of deadwood in the forest. This is related to the collection of deadwood by local people who remove deadwood with different levels of intensity. [ABSTRACT FROM AUTHOR]

The study aimed to quantify annual mortality and recruitment rates on permanent research plots in the Badínsky prales old-growth forest. The data measured in four stands originate from six censuses, which together cover a 48-year period. The mean annual mortality rate reached 4.2% (DBH > 2 cm) or 2.3% (DBH > 8 cm). The mortality peaked in the first part of the observation period, probably indicating an intermediate disturbance activity, and the subsequent declining trend led to minimum annual mortality during the last 20 years. We found substantially higher fir mortality in comparison with beech, primarily during the first decades of the measurement period. Among three size categories, the stems with DBH 2-8 cm showed the highest mortality rate. We detected the minimum fir recruitment rate throughout the observation period; on the other hand, the beech recruitment rate was relatively high responding to the open canopy. Standing and lying deadwood volumes indicated similar trends like mortality did, and high values of fir standing deadwood observed during the first decades can signify that a relatively high proportion of mortality was related to the fir decline caused by air pollution.

The objective of the manuscript was to study the effects of dead wood on macroinvertebrates (MI) assemblages occupying different habitat patches. Three streams were studied, with control and wooded sections in each stream from which MI were sampled for all substrate types (wood, fine detritus, gravel, sand). This contribution deals with three German streams Ihle, Nieplitz, and Verlorenwasser, which belong to the stream type 14 (sand-dominated lowland stream) and are located in the landscape unit Fläming. This type of stream, where large wood could be most influential, has been relatively understudied. This study focused on quantifying substrate distribution and macroinvertebrate taxonomy and performing statistical analysis of MI densities with regard to substrate type. The area-specific invertebrate assemblages were differentiated for MI density, dry matter density and taxonomic richness of invertebrates. In addition to macroinvertebrates, a special focus was on aquatic and semi-aquatic insects. There were significant differences between the control and wooden sections. The macroinvertebrate assemblages (individual density, dry matter density and species richness) of the detritus of the wood sections only in the Verlorenwasser was significantly and positively affected (two or three times) by the deadwood. Detritus in the wood sections of the Nieplitz and Verlorenwasser contained more sensitive species like EPT than detritus from the control sections. On the other hand, no significant difference in MI populations were determined for the sand of the wood sections compared to the sand of the control sections. In all water bodies, the wood substrate promoted all investigated indicators of macrozoobenthos as compared to sand of the wood sections. Detritus significantly promoted macrozoobenthos colonization in the wood sections as compared to sand of the Nieplitz and the Verlorenwasser. The MI density and dry matter density in the Ihle was also significantly promoted by detritus, although not significantly with regard species richness. Two significant correlations were also identified. The more sand that was present in the Ihle and the Verlorenwasser, the more the macroinvertebrate assemblages were inhibited. Additionally, the larger the area of detritus in the Ihle and the area of wood in the Nieplitz, the more MI populations were encouraged. The influence of the deadwood position on MI was also investigated, but there was no significant difference. Incline bridges, flow guides and parallel wood position types were settled in similar quality and quantity.

The occurrence of deadwood is inevitable during the process of plantation conversion, but the influences of conversion and the potential environmental effect on deadwood species diversity remain unclear. We established two fixed plots in Chinese fir thinned forest (TF) and Chinese fir and Michelia macclurei Dandy mixed forest (MF) (100 × 80 and 120 × 60 m2, respectively). We classified the deadwood into groups based on origin and by status, and analyzed deadwood species diversity using four common diversity indices. We also investigated the contribution of topographic factors to tree mortality using redundancy analysis. The species composition of deadwood differed markedly between the MF and TF. The species diversity and variety of deadwood status were greater for the TF than MF, although abundance was lower. Topography was poorly correlated with deadwood in the MF, while in the TF, altitude was strongly correlated with deadwood from Chinese fir, shade-intolerant late-coming populations, and fallen wood. Slope was negatively correlated with late-coming populations and fallen wood, but deadwood correlations with convexity were weak. These results indicate that cultivation methods strongly alter the species composition, status, abundance and diversity of deadwood in plantations. Topographic factors and targeted cultivation practices promote the formation of deadwood. [ABSTRACT FROM AUTHOR]

Deadwood is an important indicator of biodiversity in forest ecosystems. Identifying areas with large density of standing dead trees through field inventory is challenging, and remotely sensed data can provide a more systematic approach. In this study, we used metrics derived from airborne laser scanning (ALS) data (7.1 points m−2) and vegetation indices from optical images (HySpex sensor VNIR-1800: 0.3 m, SWIR-384: 0.7 m) to predict the presence of standing dead trees over a 15.9 km2 managed forest in Southern Norway. The dead basal area (DBA) of 40 sample plots was computed and used to classify the plots into presence/absence of standing dead trees. An area-based approach (ABA) using logistic regression was initially tested, but due to limited ground reference information, no statistically significant models could be formulated. A tree-based approach (TBA) was used to overcome this limitation. It identified trees on the ALS point cloud with a local maxima function and used a vegetation index to determine if the trees were dead. Between 18% and 42% of the predicted area with standing dead trees intersected a field recorded validation dataset. The TBA provided a good alternative to area-based regression models in the context of few standing dead trees. [ABSTRACT FROM AUTHOR]

Soil organic matter (SOM) forms along a continuum from individual particles, pores, and aggregates to litter–soil profiles and larger ecosystems such as forests. However, forest management of SOM stocks and the carbon therein requires knowledge on which processes and factors at which scales determine SOM formation from forest biomass. As evident from woody debris at the profile scale, SOM forms through additions, transformations, translocations, and removals of litter by soil organisms and environmental components. Yet SOM stocks only increase if litter additions‐to‐removals are out of steady state or enter a new steady state that ignores older litter. Both happen through disturbance and self‐selecting feedback processes in ecosystems consisting of autotrophs, heterotrophs, and their physical environment. One such positive feedback process is litter‐SOM transformation by heterotrophs that releases nutrients that promote plant productivity and thus litter input. Stocks of litter‐SOM, heterotrophs, nutrients, and plants thus exhibit Lotka–Volterra dynamics (i.e., predator–prey interactions) and only increase when attractor states (i.e., steady series or sets of states) change due to disturbance. Evidence of evolving feedback processes and disturbance in SOM would help identify limits, potentials, and precariousness of ecosystems in light of global change, but remains to be found. [ABSTRACT FROM AUTHOR]

Deadwood is an important key ecological element for forest ecosystem biodiversity. Its low occurrence, especially in managed forests, makes inventory through field campaigns challenging. Remote sensing can provide a more objective and systematic approach to detect deadwood for large areas. Traditional area-based approaches have, however, shown limitations when it comes to predicting rare objects such as standing dead trees (SDT). To overcome this limitation, this study proposes a tree-based approach that uses a local maxima function to identify trees from airborne laser scanning (ALS) and optical data, and predict their status, i.e., living or dead, from normalized difference vegetation index (NDVI). NDVI was calculated from aerial images (hyperspectral and simulated aerial image) and from satellite images (PlanetScope and Sentinel-2). By comparing the different remotely sensed data sources, we aimed to assess the impact of spatial and spectral resolutions in the prediction of SDT. The presence/absence of SDT was perfectly predicted by combining trees identified using ALS-derived canopy height models with spatial resolutions between 0.75 m and 1 m and a search window size of 3 pixels, and NDVI computed from aerial images to predict their status. The presence/absence of SDT was not predicted as accurately when using NDVI computed from satellite images. A root-mean-square deviation of around 35 trees ha−1 was obtained when predicting the density of SDT with NDVI from aerial images and around 60 trees ha−1 with NDVI from satellite images. The tree-based approach presented in this study shows great potential to predict the presence of SDT over large areas. [ABSTRACT FROM AUTHOR]

The patterns of successional change of decomposer communities is unique in that resource availability predictably decreases as decomposition proceeds. Saproxylic (i.e. deadwood‐dependent) beetles are a highly diverse and functionally important decomposer group, and their community composition is affected by both deadwood characteristics and other environmental factors. Understanding how communities change with faunal succession through the decomposition process is important as this process influences terrestrial carbon dynamics.Here, we evaluate how beta‐diversity of saproxylic beetle communities change with succession, as well as the effects of different major drivers of beta‐diversity, such as deadwood tree species, spatial distance between locations, climate and forest structure.We studied spatial beta‐diversity (i.e. dissimilarity of species composition between deadwood logs in the same year) of saproxylic beetle communities over 8 years of wood decomposition. Our study included 379 experimental deadwood logs comprising 13 different tree species in 30 forest stands in Germany. We hypothesized that the effects of tree species dissimilarity, measured by phylogenetic distance, and climate on beta‐diversity decrease over time, while the effects of spatial distance between logs and forest structure increase.Observed beta‐diversity of saproxylic beetle communities increased over time, whereas standardized effects sizes (SES; based on null models) of beta‐diversity decreased indicating higher beta‐diversity than expected during early years. Beta‐diversity increased with increasing phylogenetic distance between tree species and spatial distance among regions, and to a lesser extent with spatial distance within regions and differences in climate and forest structure. Whereas effects of space, climate and forest structure were constant over time, the effect of phylogenetic distance decreased.Our results show that the strength of the different drivers of saproxylic beetle community beta‐diversity changes along deadwood succession. Beta‐diversity of early decay communities was strongly associated with differences among tree species. Although this effect decreased over time, beta‐diversity remained high throughout succession. Possible explanations for this pattern include differences in decomposition rates and fungal communities between logs or the priority effect of early successional communities. Our results suggest that saproxylic beetle diversity can be enhanced by promoting forests with diverse tree communities and structures. [ABSTRACT FROM AUTHOR]

Deadwood decomposition and other environmental processes mediated by microbial communities are generally studied with composite sampling strategies, where deadwood is collected from multiple locations in a large volume, that produce an average microbial community. In this study, we used amplicon sequencing to compare fungal and bacterial communities sampled with either traditional, composite samples, or small, 1 cm3 cylinders from a discrete location within decomposing European beech (Fagus sylvatica L.) tree trunks. We found that bacterial richness and evenness is lower in small samples when compared to composite samples. There was no significant difference in fungal alpha diversity between different sampling scales, suggesting that visually defined fungal domains are not restricted to a single species. Additionally, we found that composite sampling may obscure variation in community composition and this affects the understanding of microbial associations that are detected. For future experiments in environmental microbiology, we recommend that scale is explicitly considered as a factor and properly selected to correspond with the questions asked. Studies of microbial functions or associations may require samples to be collected at a finer scale than is currently practised. [ABSTRACT FROM AUTHOR]

The habitat quality of the littoral zone is of key importance for almost all lentic fish species. In anthropogenically created gravel pit lakes, the littoral zone is often structurally homogenized with limited fish habitats. We supplemented deadwood brush piles in the littoral zone of eight gravel pit lakes and investigated the diurnal and seasonal use of this and other typical microhabitats by six dominant fish species. Shoreline habitats were sampled using point abundance electrofishing during day and night in all four seasons, and patterns of fish abundance were compared amongst unstructured littoral habitats, emerged macrophytes and brush piles. We caught a total of 14,458 specimens from 15 species in the gravel pit lakes. Complex shoreline structures were used by all fish species that we examined, especially during daytime, whilst the use of unstructured habitats was highest during night. The newly added brush piles constituted suitable microhabitats for selected fish species, perch (Perca fluviatilis), roach (Rutilus rutilus) and pike (Esox lucius), particularly during winter. Supplemented deadwood provides suitable fish habitat in gravel pit lakes and may to some degree compensate for the loss of submerged macrophytes in winter by offering refuge and foraging habitat for selected fish species. [ABSTRACT FROM AUTHOR]

Beetles are one of the most diverse and often highly specialized groups among saproxylic organisms and play a key role in forest dynamics. To develop conservation plans in forests threatened by human activities, such as construction sites, it is crucial to identify key parameters characterizing forest structure in turn influencing saproxylic beetle diversity and abundance. Here, we investigate the difference in forest structure parameters and their cascading effect on saproxylic beetle communities between a forest site affected by the construction site expansion of the Turin–Lyon High-Speed Railway Line and a nearby second forest site. Our study showed differences in forest structure parameters between the two sites, in particular in the overall volume and diameter of coarse woody debris and in standing dead tree abundance. Even saproxylic beetle community structure was different between the two sites and this difference was linked to the different abundance and species richness of standing dead trees. Our findings provide information for the development of a local conservation plan for the saproxylic beetle community within forest habitats. Increasing the volume of deadwood and enriching tree diversity can locally sustain abundant and diverse communities and, eventually, support those species that are threatened by the building site expansion. [ABSTRACT FROM AUTHOR]

For the last three decades, the area of old-growth forest stands in Europe has continued to increase as has their importance in achieving forest-related policy goals. This has triggered an increase in research interest in old-growth forests, both from climate change mitigation and biodiversity protection perspectives. However, carbon stock in old-growth stands in European hemiboreal forests had not been systematically studied. Therefore, in this article, we characterize differences in carbon stock between mature and old-growth stands on fertile mineral soils in hemiboreal Latvia to contribute to the understanding of carbon storage changes under different management strategies for forest lands. Carbon stock varied significantly both between old-growth stands of different dominant tree species and between mature (1.9–2.3 times younger) and old-growth stages of the same dominant species in forest stands. The carbon stock of tree biomass and deadwood was larger in old-growth stands, but their mean annual carbon stock change was significantly lower than in mature stands (27% to 47% depending on dominant tree species). Old-growth stands can serve as carbon reservoirs in areas with limited natural disturbances; however, for maintenance of climate neutrality, it is essential to expand the area of managed stands with larger annual carbon stock increase. Study Implications : Forest ecosystems play a major role in regulation of global climate: They can store high quantities of carbon and also can gain or lose it rather quickly. For the last three decades, the area of old-growth forest stands in Europe has continued to increase as has their importance in achieving forest-related policy goals. Old-growth forests can represent the baseline carbon-carrying capacity in particular conditions. Therefore, we characterized differences in carbon stock between mature and old-growth stands on fertile mineral soils in hemiboreal Latvia to contribute to the understanding of carbon storage and for planning forest management activities. [ABSTRACT FROM AUTHOR]

Abstract Selective browsing by deer on young trees may impede the management goal of increasing forest resilience against climate change and other disturbances. Deer population density is often considered the main driver of browsing impacts on young trees, however, a range of other variables such as food availability also affect this relationship. In this study, we use browsing survey data from 135 research plots to explore patterns of roe deer (Capreolus capreolus) browsing pressure on woody plants in mountainous forests in central Europe. We fitted species‐specific generalised linear mixed models for eight woody taxa, assessing the potential effects of understory characteristics, roe deer abundance and lying deadwood on browsing intensity. Our study reveals conspecific and associational effects for woody taxa that are intermediately browsed by roe deer. Selective browsing pressure was mediated by preferences of plants, in that, browsing of strongly preferred woody taxa as for example mountain ash (Sorbus aucuparia) and of least preferred woody taxa, for example Norway spruce (Picea abies) was not affected by the surrounding understory vegetation, while browsing pressure on intermediately browsed species like for example silver fir (Abies alba) was affected by understory characteristics. Contrary to our expectations, roe deer abundance was only positively associated with browsing pressure on silver fir and bilberry (Vaccinium myrtillus), while all other plants were unaffected by deer abundance. Finally, we did not find an influence of lying deadwood volume on the browsing pressure on any woody‐plant species. Overall, our results indicate that patterns in browsing preference and intensity are species‐specific processes and are partly affected by the surrounding understory vegetation. Current management strategies that aim to reduce browsing pressure through culling may be inefficient as they do not address other drivers of browsing pressure. However, managers also need to consider the characteristics of the local understory vegetation in addition to deer abundance and design species‐specific plans to reduce browsing on woody plant taxa.

While healthy forest ecosystems deliver various services that can reduce flood risk, they can also contribute to flooding by providing wood that potentially contributes to the clogging of waterways and associated backwater effects. In this regard, deadwood, as a key aspect of healthy forests, is often in focus of post-flood disaster discourses. This research reflects on this ambiguity in the different forest management goals when it comes to managing forests for flood risk reduction versus forest health. A working definition of forest health will be presented and an overview of the different aspects of how a forest potentially can affect the flood hazard will be provided. This will refer to the ways forests influence (1) the discharge of water from the landscape into channels and (2) the characteristics of the channel and its riparian area and their respective influence on the transport of water, sediment, and debris. Often these two determining factors for the development of the flood peak are discussed separately and by different academic fields. This paper aims to connect the existing knowledge spheres and discusses the synergies and trade-offs. The review shows that the two objectives of forest health and flood risk reduction are largely synergetic. However, in direct proximity to watercourses trade-offs might occur. This is especially due to the ambivalent relation of living vegetation and deadwood to flood hazard. In places without susceptible infrastructures to clogging, deadwood and diverse vegetation structures should be supported due to their beneficial effects on water retention and channel characteristics. In places where susceptible infrastructures exist, trade-offs between the two objectives arise. Here the potential of freshly uprooted vegetation to cause damages should be reduced while maintaining the vegetation’s supportive characteristics, for example, concerning bank and slope stability. Where the risk of clogging is assessed as too high, also the selective removal or shortening of dead in-channel Large Wood can be considered. However, based on the literature review the risk deriving from dead Large Wood is evaluated as comparably low. This is related to its generally lower proportions and its smaller and less stable characteristics compared to freshly uprooted vegetation.

Abstract In the context of global change, a better understanding of the dynamics of wood degradation, and how they relate to tree attributes and climatic conditions, is necessary to improve broad‐scale assessments of the contributions of deadwood to various ecological processes, and ultimately, for the development of adaptive post‐disturbance management strategies. The objective of this meta‐analysis was to review the effects of tree attributes and local climatic conditions on the time since death of coarse woody debris ranging in decomposition states. Results from our meta‐analysis showed that projected warming will likely accelerate wood decomposition and significantly decrease the residence time in decay stages. By promoting such a decrease in residence time, further climate warming is very likely to alter the dynamics of deadwood, which in turn may affect saproxylic biodiversity by decreasing the temporal availability of specific habitats. Moreover, while coarse woody debris has been recognized as a key resource for bioenergy at the global scale, the acceleration of decay‐stages transition dynamics indicates that the temporal window during which dead trees are available as feedstock for value‐added products will shrink. Consequently, future planning and implementation of salvage harvesting will need to occur within a short period following disturbance, especially in warmer regions dominated by hardwood species. Another important contribution of this work was the development of a harmonized classification system that relies on the correspondence between the visual criteria used to characterize deadwood decomposition stages in locally developed systems the literature. This system could be used in future investigations to facilitate direct comparisons between studies. Our literature survey also highlights that most of the information on wood decay dynamics comes from temperate and boreal forests, whereas data from subtropical, equatorial and subarctic forests are scarce. Such data are urgently needed to allow broader‐scale conclusions on global wood degradation dynamics.

We present a data set resulting from the first round of a national monitoring program of forest reserves. It contains 9538 permanent plots, distributed across 111 study sites in mainland France (including Corsica). Notably focusing on dead wood measurement, this protocol has primarily been applied in strict forest reserves and special nature reserves (sensu Bollmann & Braunisch 2013), with 68% (6494) of the plots being currently located in strict forest reserves (unmanaged) and 24.7% (2363 plots) in forests unmanaged for at least 50 years. Sites cover a large variety of ecological conditions, from lowland to subalpine forests, but with an underrepresentation of Mediterranean forests (Table 1). The protocol assesses all the stages of a tree's life cycle, from seedling to decomposed lying dead wood. On each plot, a combination of three sampling techniques was used: (1) fixed‐area inventory for regeneration, standing dead trees, living trees, and coarse woody debris (CWD) with diameter over 30 cm; (2) transect lines for CWD with diameter <30 cm; and (3) fixed‐angle plot method for living trees with diameter at breast height (DBH) >30 cm (using a relascopic angle of 3%). Measurements include exact tree location (azimuth, distance), species, diameter(s), tree‐related microhabitats, decay stage and bark cover, and seedling cover. With ongoing climate change, the program network can also provide important information to monitor changes in forest ecosystems. It can also be used as forest management monitoring or conservation status assessment. These data are freely available for noncommercial scientific use (Creative Commons Attribution 4.0 CC BY SA 4.0) with attribution, and this paper must be cited if this material is reused. [ABSTRACT FROM AUTHOR]

Achieving an understanding of species’ temporal and spatial abundance patterns is a prerequisite for proper conservation and management decisions. Little is known of the ecological indicators of census size or biomass of terrestrial amphibian communities and historical estimates of population size are rare. Here we took advantage of abundance and biomass data collected in 1967/1968 for a leaf-litter amphibian community in Niepołomice Forest (NF) in south-central Poland. Using the same technique (removal sampling), we censused the amphibian community of this forest 50 years later (2016/2017), spatially matching a subset of current plots with the historical sampling sites. Averaged over all plots, we revealed at least a fourfold decline in amphibian abundance from 2817 ± 776 individuals/ha in 1967 to 674 ± 508 individuals/ha currently, paralleled by a decline in biomass from roughly 15.5 ± 1.7 to 3.8 ± 3.1 kg/ha. The decline was more striking (over 15-fold) for current plots placed in the same forest division as the historical plots (mean counts of 157 ± 103 individuals/ha corresponding in biomass to 1.0 ± 0.5 kg/ha). We also recorded a change in species composition between surveys, and propose that conversion of aquatic habitat and forest succession have decreased amphibian diversity and abundance in NF. Further, we estimated densities of anuran amphibians in forest plots differing in management regime and local habitat characteristics for contemporary plots (all historical plots were placed in managed forest). We found that unmanaged, old growth forest plots with coarse woody debris on the forest floor held on average twice as many anurans compared to plots in managed stands. Average body condition of the most common species, Rana temporaria, measured as a scaled mass index, was enhanced in plots situated in old growth forest. Our findings suggest that the preservation of old growth forests containing coarse woody debris may boost anuran abundance, biomass and body condition, and has the potential to buffer against long-term demographic decline. Moreover, the retention of deadwood could be a means of increasing the conservation potential of managed forests for terrestrial amphibian communities.

The study aimed to quantify annual mortality and recruitment rates on permanent research plots in the Badínsky prales old-growth forest. The data measured in four stands originate from six censuses, which together cover a 48-year period. The mean annual mortality rate reached 4.2% (DBH > 2 cm) or 2.3% (DBH > 8 cm). The mortality peaked in the first part of the observation period, probably indicating an intermediate disturbance activity, and the subsequent declining trend led to minimum annual mortality during the last 20 years. We found substantially higher fir mortality in comparison with beech, primarily during the first decades of the measurement period. Among three size categories, the stems with DBH 2-8 cm showed the highest mortality rate. We detected the minimum fir recruitment rate throughout the observation period; on the other hand, the beech recruitment rate was relatively high responding to the open canopy. Standing and lying deadwood volumes indicated similar trends like mortality did, and high values of fir standing deadwood observed during the first decades can signify that a relatively high proportion of mortality was related to the fir decline caused by air pollution. [ABSTRACT FROM AUTHOR]

The objective of the manuscript was to study the effects of dead wood on macroinvertebrates (MI) assemblages occupying different habitat patches. Three streams were studied, with control and wooded sections in each stream from which MI were sampled for all substrate types (wood, fine detritus, gravel, sand). This contribution deals with three German streams Ihle, Nieplitz, and Verlorenwasser, which belong to the stream type 14 (sand-dominated lowland stream) and are located in the landscape unit Fläming. This type of stream, where large wood could be most influential, has been relatively understudied. This study focused on quantifying substrate distribution and macroinvertebrate taxonomy and performing statistical analysis of MI densities with regard to substrate type. The area-specific invertebrate assemblages were differentiated for MI density, dry matter density and taxonomic richness of invertebrates. In addition to macroinvertebrates, a special focus was on aquatic and semi-aquatic insects. There were significant differences between the control and wooden sections. The macroinvertebrate assemblages (individual density, dry matter density and species richness) of the detritus of the wood sections only in the Verlorenwasser was significantly and positively affected (two or three times) by the deadwood. Detritus in the wood sections of the Nieplitz and Verlorenwasser contained more sensitive species like EPT than detritus from the control sections. On the other hand, no significant difference in MI populations were determined for the sand of the wood sections compared to the sand of the control sections. In all water bodies, the wood substrate promoted all investigated indicators of macrozoobenthos as compared to sand of the wood sections. Detritus significantly promoted macrozoobenthos colonization in the wood sections as compared to sand of the Nieplitz and the Verlorenwasser. The MI density and dry matter density in the Ihle was also significantly promoted by detritus, although not significantly with regard species richness. Two significant correlations were also identified. The more sand that was present in the Ihle and the Verlorenwasser, the more the macroinvertebrate assemblages were inhibited. Additionally, the larger the area of detritus in the Ihle and the area of wood in the Nieplitz, the more MI populations were encouraged. The influence of the deadwood position on MI was also investigated, but there was no significant difference. Incline bridges, flow guides and parallel wood position types were settled in similar quality and quantity. [ABSTRACT FROM AUTHOR]

The forest‐floor litter layer can retain substantial volumes of water, thus affecting evaporation and soil‐moisture dynamics. However, litter layer wetting/drying dynamics are often overlooked when estimating forest water budgets. Here, we present field and laboratory experiments characterizing water cycling in the forest‐floor litter layer and outline its implications for subcanopy microclimatic conditions and for estimates of transpiration and recharge. Storage capacities of spruce needle litter and beech broadleaf litter averaged 3.1 and 1.9 mm, respectively, with drainage/evaporation timescales exceeding 2 days. Litter‐removal experiments showed that litter reduced soil water recharge, reduced soil evaporation rates, and insulated against ground heat fluxes that impacted snowmelt. Deadwood stored ~0.7 mm of water, increasing with more advanced states of decomposition, and retained water for >7 days. Observed daily cycles in deadwood weight revealed decreasing water storage during daytime as evaporation progressed and increasing storage at night from condensation or absorption. Water evaporating from the forest‐floor litter layer modulates the subcanopy microclimate by increasing humidity, decreasing temperature, and reducing VPD. Despite the relatively small litter storage capacity (<3.1 mm in comparison to ~102 mm for typical forest soil rooting zones), the litter layer alone retained and cycled 18% of annual precipitation, or 1/3 of annual evapotranspiration. These results suggest that overlooking litter interception may lead to substantial overestimates of recharge and transpiration in many forest ecosystems. [ABSTRACT FROM AUTHOR]

Cork oak landscapes are fascinating ecosystems, historically managed for cork extraction. The persistence in this habitat of many hollow veteran trees provides suitable micro‐habitats for saproxylic beetles.We investigated the saproxylic beetle community of two isolated cork oak woodlands of central Italy with different degree of recovery after human transformation: (1) an open woodland and (2) a dense mixed woodland, both dominated by cork oak trees.We found endemic, rare and threatened saproxylic beetles in both the areas, confirming the important conservation value of cork oak landscapes. In the open woodland we observed a higher number of species in all trophic categories, except for mycophagous specialists. Several microhabitat variables reflected the different stage of recovery of the two woodlands.Our findings suggest the crucial role of diversified environments in protected areas: even a small difference in the degree of recovery (i.e., tree closeness) can affect the number of beetle species. Specifically, we found (1) more xerophilous species in the open woodland and (2) more mesophilous species in the dense mixed woodland. [ABSTRACT FROM AUTHOR]

As a result of the progressing climate changes, there is an increase in the volume of pine deadwood harvested each year from Polish forests. Its presence is an important part of the forest ecosystem; however, there are some indications that the material obtained from dying trees can be characterized by lower quality and properties. Taking into account the growing issue of tree dieback, the volume of pine wood annually harvested in Poland, and the importance of wooden products from an economic standpoint, preliminary research aimed at recognizing the process and its effect on the mechanical properties was conducted. Model trees in Brzeg Forest District were selected based on the crown defoliation. The properties of wood obtained from trees representing three different categories of soundness were determined according to the relevant standards. Based on the results of density, modulus of elasticity, bending strength, and compressive strength, it was found that there were statistically significant differences in wood quality depending on the condition of the tree. The results were particularly interesting in the case of compressing strength, where a healthy tree of lower density showed a similar strength to a dying tree with a much higher density. [ABSTRACT FROM AUTHOR]

Deadwood is one of the principal components of forest ecosystems. It completes numerous nature conservation and ecological functions. The work aimed to assess the reserves of woody detritus in the mixed forest of Slobozhanskyi National Nature Park (NNP) of natural origin. The research was carried out in an 86-year-old forest on fresh and fertile soils. Dead wood fractions, tree species, components, and classes of destruction were assessed on fixed area sample plot. The volume of woody detritus (WD) in the forest ecosystem is 21.8 m3·ha-1. It consists of fallen dead trunks and dead branches, which make up 75.7% of the total WD. Standng dead trunks (snags) account for the remaining 24.3%. The main part of the volume of dead wood formed by three tree species: Tilia cordata Mill., Pinus sylvestris L. and Quercus robur L. The share of these species together was 78.0%. The WD belonged from the I to V class of destruction. At the same time, the WD of the II class of decomposition was 52.5% had an advantage. The volume of snags was 5.3 m3·ha-1. In terms of species composition, Q. robur, Acer platanoides L., T. cordata, and P. sylvestris had a significant advantage. In the total volume of snags, the wood of the I class of destruction significantly prevailed at 67.9%, and the woody volume of the II class was 32.1%. Logs had a reserve of 16.5 m3·ha-1. The species composition dominated by wood detritus of T. cordata (35.8%), slightly fewer detritus of P. sylvestris (31.5%), and Betula pendula Roth. (22.4%). The fallen dead wood were represented by five classes of destruction. The biggest variety of fallen dead wood by classes of destruction was characteristic of T. cordata. A low amount of detritus are associated with a short period of strict protection of the studied forest ecosystem. [ABSTRACT FROM AUTHOR]

Fallen tree mapping provides valuable information regarding the ecological value of boreal forests. Airborne laser scanning (ALS) enables mapping fallen trees on a large scale. We compared the performance of line-detection-based individual fallen tree detection when using moderate point density ALS data (15 points/m2) and high-point-density unmanned aerial vehicle-based laser scanning (ULS) data (285 points/m2). Furthermore, we inspected the dataset and detection methodology-related factors impacting performance in each case. The results of this study showed that increasing the point density of the laser scanning dataset enables the detection of a larger proportion of fallen trees. However, based on our experiment, a line-detection-based fallen tree detection approach is sensitive to noise, thus generating a large number of false detections, especially with high-point-density data. Different types of filters, such as a simple height-based filter and machine-learning-based filters, can be used for reducing noise. However, using such filters is always a compromise, as in addition to reducing noise and thus false detections, they also reduce the number of true detections. Hence, a less noise-sensitive fallen tree detection method utilizing the finer details visible in high-density point clouds could be more suitable for high-point-density laser scanning data. [ABSTRACT FROM AUTHOR]

Questions: Do forest structural parameters related to stand heterogeneity enhance functional diversity (FD) of understorey plant communities? Do FD and functional composition of understorey plant communities vary between high‐forest (HF) and old coppices‐with‐standard (oldCWS) management types? Are HF stands characterized by a higher FD than oldCWS? Location: Submediterranean beech forests of Montagne della Duchessa Reserve (central Italy). Methods: We sampled 57 (20 m × 20 m) forest plots, 29 oldCWS and 28 HF stands, where we recorded plant species cover abundance. We used Leaf–Height–Seed and clonal traits, and run multiple separate linear models to quantify the effect of forest structural parameters and management types on FD and functional composition of understorey plant communities. Results: We found that increasing lying deadwood enhanced FD of specific leaf area (SLA) through micro‐environmental heterogeneity of soil fertility regardless of management type. We also found that increased horizontal stratification filtered the range of plant sizes, probably through light reduction. HF management enhanced FD of SLA and clonal traits through micro‐environmental heterogeneity, while reducing the FD of plant size and seed mass. HF tended to select plant communities characterized by high resource acquisition strategies but lower persistence between ramets, possibly as an effect of more mature forest conditions. Conclusion: Our study suggests that understorey plant community diversity and composition change in response to forest structure and management. Combining Leaf–Height–Seed with clonal traits offers a promising framework for understanding and predicting plant response to management practices. [ABSTRACT FROM AUTHOR]

Non‐native tree species are widely used in forest plantations. This may have negative consequences for biodiversity. Hitherto, most studies have compared species diversity between native and non‐native forest stands, which makes it difficult to separate the impact of tree species per se from stand characteristics. Our study, conducted in the south of Sweden, compares saproxylic beetle diversity across different nutritional groups, in dead wood of two native and four non‐native tree species in a block design after one and three seasons. Such an approach allows analysis of the impact of non‐native tree species per se.Mean species richness (± SD) per log was lower in non‐native than in native tree species (non‐native trees: lodgepole pine: 10.7 (± 5.3); Sitka spruce: 8.5 (± 4.3), Douglas fir: 7.1 (± 4.3), Japanese larch 9.4 (± 4.6); native trees: Norway spruce: 12.0 (± 6.0), Scots pine: 12.3 (± 5.2)). Sample‐based rarefaction revealed that when only native tree species were pooled, the species richness was higher than for all tree species combined. The difference in species composition among tree species was strongly driven by bark and wood consumers in the first season, while for predators and fungivores, the differences were smaller. Species composition differed most in the first season.Dissimilarity in beetle species composition was positively correlated with phylogenetic distances of the tree species. Species richness was lower in non‐native tree species that are only remotely related to native trees species. Of the studied non‐native tree species, lodgepole pine was more closely related to native tree species and consistently harboured higher species richness.Synthesis and applications. Although non‐native tree species also harbour saproxylic beetle communities, the use of non‐native tree species, especially those only remotely related to native tree species, reduces local diversity of saproxylic beetles. Thus, for biodiversity conservation, an extensive use of non‐native tree species is not recommended as this increases the risk of losing forest biodiversity, especially when they are only distantly related to native tree species. [ABSTRACT FROM AUTHOR]

Snags are an important component of beech forests that promote biodiversity. However, their occurrence is completely marginal in managed stands. Creating snags in these stands would greatly enhance biodiversity. We investigated whether snag dimensions were important for saproxylic beetle richness since they were easily transferable parameters to forest management and assessed the presence of other snag microhabitats affecting beetle communities. Data collection was performed using passive flight traps placed on thirty snags in a recent beech reserve. A total of 6706 adults belonging to 231 saproxylic species (53 Red List species, 23%) were captured. The results showed that the most important snag parameters were the diameter (thickness) and canopy openness of the surrounding stands. The occurrence of Fomes fomentarius, the volume of snag and decay class 3 were marginally significant in terms of the preference of all saproxylic species. Alpha diversity was reduced by an advanced degree of decay and a surprisingly deep stem cavity. After dividing snag thickness into categories (<35 cm; 35-70 cm and >70 cm DBH), we found that categories with snag diameter greater than 35 cm showed little differences in all saproxylic and Red List species richness and diversity indices and exhibited the highest similarity in beetle communities. Regarding recommendations to forest managers in terms of optimization and simplification of practical procedures, we suggest actively creating high stumps to act as snags greater than 35 cm in DBH diameter to promote biodiversity in beech management stands. [ABSTRACT FROM AUTHOR]

Several adults and larvae of Pytho abieticola were discovered in 2021 and 2022 at three different localities in two regions of Switzerland, the Jura mountains and the Swiss National Park in the Eastern Alps. This very rare saproxylic beetle has not been detected in Switzerland so far. Considered a relict of primeval forests, it is in strong decline or has already disappeared from large areas of Central Europe. The isolated Swiss populations are the westernmost in its distributional range. Information on the ecology and distribution of P. abieticola in Switzerland and Europe is provided and criteria to distinguish P. abieticola from the congeneric and syntopic P. depressus are defined. [ABSTRACT FROM AUTHOR]

Retention forestry has become increasingly popular in recent decades. Although retained trees have a high post-harvest mortality rate, little is known about the role of dead retention trees in the conservation of lichen and bryophyte species. In this study, species composition and richness of bryophytes and lichens on living trees, and snags and logs of dead retention trees was assessed in 20 young stands in Latvia. The goal was to compare how the species richness and composition differ between retention tree structure types (living trees, snags, and logs). The results showed that higher bryophyte and lichen species richness per tree was found on logs and snags compared to living trees. Species composition significantly differed between retention tree structure types. Snags and logs hosted a higher number of woodland key habitat species than living trees. Retention tree species had a significant effect on bryophyte species richness on living trees, while tree species and diameter at breast height were important for bryophyte diversity on snags, and stage of decay on logs. In contrast, the number of lichen species on snags and logs was affected only by retention tree species while none of these factors had a significant effect on lichen species on living trees. As a conclusion, the conservation of bryophyte and lichen diversity on retention trees needs to consider also their role as deadwood substrates after their death. • Bryophyte and lichen richness were compared on snags, logs and living retention trees. • Logs and snags had more bryophyte and lichen species than living retention trees. • More woodland key habitat species were on snags and logs compared to living trees. • Factors influencing species richness differ between living and dead retention trees. • Dead retention trees are valuable substrate for bryophyte and lichen conservation. [ABSTRACT FROM AUTHOR]

In recent years, the loss of biodiversity occurred worldwide has called for the creation of various indicators aimed to assess the health status of the environment. Due to the increase of forest areas throughout Europe, different ecological indicators for the assessment of naturalness and health of forest ecosystems are being theorized and modelled, with relevant implications both for planning current and future management of forest ecosystems and to control their evolution over time. In this study, a new indicator of the ecological naturalness of forest habitats is proposed with the aim of providing an intuitive and straightforward tool for the harmonization and optimization of sampling efforts in similar projects (such as those proposed by Forest Europe). To this end, a limited number of variables concerning deadwood, climate, fauna, forest typology, and biotic and abiotic stress of trees have been combined into an indicator which reflects the overall health status and naturalness of forest ecosystems. Future studies and the collaboration between different research groups are desirable in order to validate the theorethical indicator proposed here and test its effectiveness and ease-of-use in projects focused on assessing the naturalness of forest ecosystems.

In sustainable forest resource management, establishing forest conservation areas is important to maintain forest biodiversity. However, assessing the conservation value of forests is challenging because the target areas are often both large and remote. We explored using dense airborne laser scanning (ALS) data to estimate conservation values. Field data were collected at sites in Sweden for standing deadwood (S trees), laying deadwood (L trees), and trees considered particularly important for conserving biodiversity (N trees), and forest conservation values were determined using a commonly employed method in the field. A template matching method was then used to detect L, S and N trees from ALS data. L trees were identified from linear features in the point cloud above the ground, with a 52 % detection error rate. S and N trees were identified from unusually small or large crown diameters, with 71 % and 83 % error rates, respectively. We also tested the relationships between the three types of indicator tree, their summed values and the field inventory-assessed conservation values. Regressions between the assessed conservation values and ALS indicators were most robust comparing the three test sites when using the summed number of L, S, and N trees. A wall-to-wall map covering a 3 km × 4 km area was generated using Kernel density estimation of the summed number of ALS-derived indicators, to represent relative conservation values. The map was validated using 10 1-ha plots, and yielded an R2 value of 0.6 for predicted conservation values at the plot level. We conclude that ALS data can be used to map forest conservation values and inform decisions about which forests should be used for timber production and which should be set aside as conservation areas. The maps could also be used as a data source for habitat analysis.

Snags are an important component of beech forests that promote biodiversity. However, their occurrence is completely marginal in managed stands. Creating snags in these stands would greatly enhance biodiversity. We investigated whether snag dimensions were important for saproxylic beetle richness since they were easily transferable parameters to forest management and assessed the presence of other snag microhabitats affecting beetle communities. Data collection was performed using passive flight traps placed on thirty snags in a recent beech reserve. A total of 6706 adults belonging to 231 saproxylic species (53 Red List species, 23%) were captured. The results showed that the most important snag parameters were the diameter (thickness) and canopy openness of the surrounding stands. The occurrence of Fomes fomentarius, the volume of snag and decay class 3 were marginally significant in terms of the preference of all saproxylic species. Alpha diversity was reduced by an advanced degree of decay and a surprisingly deep stem cavity. After dividing snag thickness into categories (70 ​cm DBH), we found that categories with snag diameter greater than 35 ​cm showed little differences in all saproxylic and Red List species richness and diversity indices and exhibited the highest similarity in beetle communities. Regarding recommendations to forest managers in terms of optimization and simplification of practical procedures, we suggest actively creating high stumps to act as snags greater than 35 ​cm in DBH diameter to promote biodiversity in beech management stands.

In tropical forests, especially in the Southeast Asia, there are only fragmentary estimates of coarse woody debris (CWD) pools and dynamics. Our study examines the volume and structural diversity of CWD in forests not affected by commercial felling in the territories of the Bidoup Núi Bà and Bù Gia M p National Parks of the Republic of Vietnam. In the lowland Dipterocarp forests of Bù Gia M p National Park, the average volume of CWD was almost two times lower than the average CWD stock in the mixed montane forests of Bidoup Núi Bà national park: 44 m3 ha–1 versus 78 m3 ha–1. The mass of CWD depended linearly on its volume and averaged 24 t ha–1. The projective cover of CWD averaged 269 m2 ha–1. Snags prevailed among the substrate categories (position types), accounting for 42 and 31% in the Bidoup Núi Bà and Bù Gia M p forests, respectively. The proportion of large branches in the montane forests of Bidoup Núi Bà National Park was 8%, while in the lowland forests of Bù Gia M p it reached 33% of the CWD volume. Very high termite activity was noted in the Bù Gia M p National Park—in 73% of the studied CWD pieces. The percentage of thermite tunnels partially filled with soil was, on average, 32% of the CWD volume. The high projective cover of CWD with various types of mass loss: consumption by invertebrates, white- and brown-rot decay suggests a significant role of CWD in the soil-forming processes. The similarities were revealed in the volume and size of CWD in the studied monsoon tropical forests of South Vietnam and in the primeval European boreal Norway spruce forests with fine-scale gap dynamics. The predominance of snags among the CWD categories and the nearly bell-shaped distribution of the CWD volume by decay classes complement the similarity of the CWD pool in tropical lowland and montane mixed forests with that in uneven-aged spruce boreal forests. However, a high proportion of branches in the structure of CWD, especially in lowland deciduous mixed forests distinguishes the CWD in tropical forests from the CWD in boreal and temperate forests. [ABSTRACT FROM AUTHOR]

Environmental filters—including those resulting from biotic interactions—play a crucial role during the assembly of ecological communities. The importance of scale has thereby been acknowledged but filters at different scales have rarely been quantified in relation to each other, although these hierarchically nested filters eventually determine which communities assemble from a regional species pool.Saproxylic beetles offer an ideal system to study such hierarchically nested environmental filters. Three steps of filtering during the community assembly of these deadwood‐dependent beetles are proposed. First, starting from a regional species pool, species must disperse to forest sites. Second, within a site, individuals need to find a patch with preferred microclimatic conditions. Third, the conditions of a single deadwood object (i.e. tree species identity, decomposition stage) at this patch will determine, which species colonise and establish.To study these hierarchical filters, we used unique long‐term data ets of saproxylic beetle diversity from trap catches at 29 sites and from emergence traps on 694 experimentally installed deadwood logs at the same sites in three regions in Germany. To relate different environmental filters to beetle assemblages, we used a set of 13 functional traits that are hypothesised to relate to different filters at different scales.We show that all three hierarchical filtering steps resulted in reductions of functional diversity and simultaneous shifts in the functional composition of beetle assemblages, reflecting the roles of different traits in response to different filters. Trait composition changed most strongly at the last filtering step, that is, depended on tree species identity and decomposition stage.We showed that if community assembly is analysed as a hierarchical multi‐step process based on data from different spatial scales, environmental filters can be quantified at these scales. As such, a better understanding of the role that different filters play at different spatial scales can be reached. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]