Forests play a vital role in mitigating climate change through their physiological functions and metabolic processes,including their ability to convert solar energy into biomolecules.However,further research is necess...Forests play a vital role in mitigating climate change through their physiological functions and metabolic processes,including their ability to convert solar energy into biomolecules.However,further research is necessary to elucidate how structural characteristics of a forest and topographic settings influence energy conversion and surface temperature of a forest.In this study,we investigated a beech forest in central Germany using airborne laser scanning(ALS)point cloud data and land surface temperature(LST)data derived from Landsat 9 satellite imagery.We constructed 30 m×30 m plots across the study area(approximately 17 km2)to align the spatial resolution of the satellite imagery with the ALS data.We analyzed topographic variables(surface elevation,aspect and slope),forest attributes(canopy cover,canopy height,and woody area index),as well as forest structural complexity,quantified by the box-dimension(Db).Our analysis revealed that LST is significantly influenced by both forest attributes and topographic variables.A multiple linear regression model demonstrated an inverse relationship(R^(2)=0.38,AIC=8105)between LST and a combination of Db,elevation,slope,and aspect.However,the model residuals exhibited significant spatial dependency,as indicated by Moran’s I test.To address this,we applied a spatial autoregressive model,which effectively accounted for spatial autocorrelation and improved the model fit(AIC=746).Our findings indicate that elevation exerts the most substantial influence on LST,followed by forest structural complexity,slope,and aspect.We conclude that forest management practices that enhance structural complexity can effectively reduce land surface temperatures in forested landscapes.展开更多
Background: Continuous Cover Forestry(CCF) is a type of forest management that is based on ecological, environmental, and biological principles. Specific definitions of CCF greatly vary and the concept usually include...Background: Continuous Cover Forestry(CCF) is a type of forest management that is based on ecological, environmental, and biological principles. Specific definitions of CCF greatly vary and the concept usually includes a number of tenets or criteria. The most important tenet of CCF is the requirement to abandon the practice of largescale clearfelling in favour of selective thinning/harvesting and natural regeneration methods.Methods: CCF is commonly believed to have its main origin in an academic debate that was conducted through publications in a number of European and North American countries towards the end of the 19th and the beginning of the 20th century. Our findings are exclusively based on a literature review of the history of CCF and they revealed that the European origins of CCF go much further back to a form of farm forestry that started to be practised in Central Europe in the 17th century. Eventually, this type of farm forestry led to the formation of the single-tree selection system as we know it today. Another influential tradition line contributing to modern CCF is individual-based forest management, which breaks forest stands down into small neighbourhood-based units. The centres of these units are dominant frame trees which form the framework of a forest stand. Consequently, management is only carried out in the local neighbourhood of frame trees. Individual-based forest management also modified inflexible area-control approaches of plantation forest management in favour of the flexible sizecontrol method.Results and conclusions: We found evidence that the three aforementioned tradition lines are equally important and much interacted in shaping modern CCF. Since CCF is an international accomplishment, it is helpful to thoroughly study the drivers and causes of such concepts. Understanding the gradual evolution can give valuable clues for the introduction and adaptation of CCF in countries where the concept is new.展开更多
Rapid urbanization has caused significant changes along the urban-rural gradient,leading to a variety of landscapes that are mainly shaped by human activities.This dynamic interplay also influences the distribution an...Rapid urbanization has caused significant changes along the urban-rural gradient,leading to a variety of landscapes that are mainly shaped by human activities.This dynamic interplay also influences the distribution and characteristics of trees outside forests(TOF).Understanding the pattern of these trees will support informed decision-making in urban planning,in conservation strategies,and altogether in sustainable land management practices in the urban context.In this study,we employed a deep learning-based object detection model and high resolution satellite imagery to identify 1.3 million trees with bounding boxes within a 250 km^(2)research transect spanning the urban-rural gradient of Bengaluru,a megacity in Southern India.Additionally,we developed an allometric equation to estimate diameter at breast height(DBH)from the tree crown diameter(CD)derived from the detected bounding boxes.Our study focused on analyzing variations in tree density and tree size along this gradient.The findings revealed distinct patterns:the urban domain displayed larger tree crown diameters(mean:8.87 m)and DBH(mean:43.78 cm)but having relatively low tree density(32 trees per hectare).Furthermore,with increasing distance from the city center,tree density increased,while the mean tree crown diameter and mean tree basal area decreased,showing clear differences of tree density and size between the urban and rural domains in Bengaluru.This study offers an efficient methodology that helps generating instructive insights into the dynamics of TOF along the urban-rural gradient.This may inform urban planning and management strategies for enhancing green infrastructure and biodiversity conservation in rapidly urbanizing cities like Bengaluru.展开更多
Plant species diversity is one of the most widely used indicators in ecosystem management.The relation of species diversity with the size of the sample plot has not been fully determined for Oriental beech forests(Fag...Plant species diversity is one of the most widely used indicators in ecosystem management.The relation of species diversity with the size of the sample plot has not been fully determined for Oriental beech forests(Fagus orientalis Lipsky),a widespread species in the Hyrcanian region.Assessing the impacts of plot size on species diversity is fundamental for an ecosystem-based approach to forest management.This study determined the relation of species diversity and plot size by investigating species richness and abundance of both canopy and forest floor.Two hundred and fifty-six sample plots of 625 m^(2) each were layout in a grid pattern across 16 ha.Base plots(25 m×25 m)were integrated in different scales to investigate the effect of plot size on species diversity.The total included nine plots of 0.063,0.125,0.188,0.250,0.375,0.500,0.563,0.750 and 1 ha.Ten biodiversity indices were calculated.The results show that species richness in the different plot sizes was less than the actual value.The estimated value of the Simpson species diversity index was not significantly different from actual values for both canopy and forest floor diversity.The coefficient of variation of this index for the 1-ha sample plot showed the lowest amount across different plot sizes.Inverse Hill species diversity was insignificant difference across different plot sizes with an area greater than 0.500 ha.The modified Hill evenness index for the 1-ha sample size was a correct estimation of the 16-ha for both canopy and forest floor;however,the precision estimation was higher for the canopy layer.All plots greater than 0.250-ha provided an accurate estimation of the Camargo evenness index for forest floor species,but was inaccurate across different plot sizes for the canopy layer.The results indicate that the same plot size did not have the same effect across species diversity measurements.Our results show that correct estimation of species diversity measurements is related to the selection of appropriate indicators and plot size to increase the accuracy of the estimate so that the cost and time of biodiversity management may be reduced.展开更多
Forest planning involves estimating the biomass of species present in the area.Two fundamental parameters are diameter and height through which it is possible to indirectly estimate of biomass present.Digitalisation o...Forest planning involves estimating the biomass of species present in the area.Two fundamental parameters are diameter and height through which it is possible to indirectly estimate of biomass present.Digitalisation of forestry operations,such as forest planning,is crucial and should be affordable and easy-to-use digital applications and open-source devices.A digital progressive web application(PWA)was designed to record measurements.The app was connected via bluetoot to an open-source IoT digital forestry caliper prototyped by modifying a commercial tree caliper.An economic analysis was carried out considering all costs necessary for the development and operation of the app on smartphones and the preparation of electronic means for creation of the digital caliper.A comparison was made between costs of detecting tree diameters through application of the technology developed compared to costs calculated by applying the use of a dendrometric caliper(three technological levels were considered:L1,L2 and L3).The PWA allowed for easy data entry and viewing,maps and tree densities.The open-source digital caliper showed accuracy and precision comparable with similar commercial devices(1.5%±0.9%and 0.0%±0.9%,respectively).Total time per operator was lower using the digital caliper.From an economic perspective,application of the digital technology was more sustainable than the traditional system.Use of the digital caliper in combination with the web application optimizes detection time of a single tree,and therefore decreases overall cost.展开更多
Prescribed burning is commonly used to maintain forest ecosystem functions and reduce the risk of future wildfires.Although many studies have investigated the response of microbial community to wildfires in forest eco...Prescribed burning is commonly used to maintain forest ecosystem functions and reduce the risk of future wildfires.Although many studies have investigated the response of microbial community to wildfires in forest ecosystems,the effects of prescribed burnings on soil microbial community structure are less studied.It is also unclear that how post-fire soil physiochemical properties changes affected soil microbial communities.Here,we studied the impacts of prescribed burning on soil microbiome in three typical temperate forests of northern China by collecting soil physicochemical and high-throughput sequencing for 16S rRNA and 18S rRNA was applied to analyze the diversity and community composition of soil microbes(bacteria and fungi).Compared with pre-fire condition,prescribed burning significantly decreased Chaol index and altered soil bacterial communities(P<0.05),whereas it had no significant effect on fungal diversity and community structure of the(P>0.05).Planctomycetes and Actinobacteria made the greatest contributions to the bacterial community dissimilarity between the pre-fire and post-fire conditions.The main variables influencing the post-fire soil microbial community structure are soil pH,available phosphorus,total nitrogen,and the ratio of soil total carbon to soil total nitrogen,which could account for 73.5% of the variation in the microbial community structure in these stands.Our findings demonstrated a great discrepancy in the responses of bacteria and fungi to prescribed burning.Prescribed burning altered the soil microbial structure by modifying the physicochemical properties.Our results pointed that it is essential to evaluate the impact of prescribed burnings on forest ecosystem functions.These findings provide an important baseline for assessing post-fire microbial recovery in the region and offer critical guidance for restoration efforts.展开更多
Forest ecosystems can be characterized by a set of catenas arranged along the slope in mountainous areas as these affect microhabitat features,which in turn influence soil properties.Heretofore,few studies have examin...Forest ecosystems can be characterized by a set of catenas arranged along the slope in mountainous areas as these affect microhabitat features,which in turn influence soil properties.Heretofore,few studies have examined how topographic variables affect soil properties and quality in semiarid regions.This study aimed to provide important insights into how catena position and shape influence soil properties,soil quality,and their interrelationships in a semiarid protected oak forest in western Iran.Basic soil properties were measured in the laboratory.In addition,the soil quality index(SQI)was calculated at different topographic positions along both convex(Λ-shaped)and concave(V-shaped)catenas at two soil depths(0-15 and 15-30 cm).The findings indicated that soil organic carbon and total nitrogen declined in the lower depth in both V-andΛ-shaped catenas and at all catena positions.The lowest porosity was observed in the lower depth at toeslope positions(TS)of both catenas.Substrate-induced respiration(SIR),microbial biomass carbon(MBC),and basal respiration(BR)were higher in the upper depths at TS positions on V-shaped catenas than onΛ-shaped catenas.These biological indices were consistently higher in the upper depths than in the lower depths across all positions of both catenas.SQI had the highest values at TS positions on both catenas and in the upper depths across all positions.Pearson correlations between soil properties indicated that SQI was most strongly and positively correlated with biological properties in both catenas.The nutrient levels,microbial activity,and soil porosity in both catena shapes and at both soil depths displayed a relatively downward trend with increasing elevation from toeslope to summit positions.The results showed that catena topographic sequence shape and position affected most of the soil properties,providing evidence of the important role of topography in creating pedodiversity in oak forest ecosystems.展开更多
Functional traits are characteristics associated with the growth,reproduction,and survival of individuals.Studying them helps us understand how species traits drive ecosystem functioning.Thus,we evaluated the differen...Functional traits are characteristics associated with the growth,reproduction,and survival of individuals.Studying them helps us understand how species traits drive ecosystem functioning.Thus,we evaluated the differences in traits and functional diversity between forest edges and interiors,and how the inclusion of intraspecific trait variation affects the assessment of functional diversity in these habitats.We sampled 10 representative forest patches,and,in each patch,we established five plots on the edge and five inside the forest,collecting leaf functional traits,allometric and wood density for all species.We assessed functional diversity using functional richness(FRic),divergence(FDiv),and dispersion(FDis).To assess the impact of incorporating intraspecific variation when comparing trait values and functional diversity indices,we established two scenarios:one that excludes intraspecific variation and another that includes it.We found that the edge and interior harbor individuals with distinct functional traits that alleviate the inherent stress of each habitat.The edge was also found to be more selective in terms of the range of functional traits,resulting in lower functional diversity.Our findings demonstrated that habitats play an important role in intraspecific trait variation(ITV)and that statistically significant differences between habitats,in relation to traits and functional diversity,were better observed with the inclusion of intraspecific variation.Our study highlights the potential of using natural forest patches to understand the edge effect,regardless of habitat loss.Additionally,we emphasize the importance of incorporating ITV into functional diversity studies,especially those on a smaller scale that incorporate quantitative variables,to better understand and predict ecological patterns.展开更多
Forest ecosystems are one of the largest terres-trial carbon(C)reservoirs on Earth and an important sink of anthropogenic CO_(2) emissions.Abiotic and biotic distur-bances such as windfalls,fires,outbreaks of insects ...Forest ecosystems are one of the largest terres-trial carbon(C)reservoirs on Earth and an important sink of anthropogenic CO_(2) emissions.Abiotic and biotic distur-bances such as windfalls,fires,outbreaks of insects or pests may negatively affect C storage in forest ecosystems decreas-ing their role as CO_(2) sink.The objective of this review was to summarize the current knowledge on the impact of large-scale forest ecosystem disturbances caused by windthrow and insect outbreaks on soil C stocks and cycles,and to gather information on the impact of restoration treatments performed in disturbed stands in the context of carbon accumulation in forest soils.Discussed were effects of wind-storms and insect outbreaks as well as impacts of various approaches of forest regeneration after disturbance on C stocks and fluxes.Disturbances decrease C stocks in forest ecosystems and turn them from C sink into C source for a certain time.Regeneration of the disturbed forest restores its role as a CO_(2) sink.In montane forests artificial afforestation seems to shorten the time of achieving C parity.However,no data exists for lowland forests.Hence,there is an urgent need for studies that assess effect of windfalls and insect outbreaks on carbon storage in forests of lowland Europe.展开更多
Neighborhood competition is a critical driver of individual tree growth,and aboveground biomass(AGB)accumulation,which together play key roles in forest dynamics and carbon storage.Therefore,accurate biomass estimatio...Neighborhood competition is a critical driver of individual tree growth,and aboveground biomass(AGB)accumulation,which together play key roles in forest dynamics and carbon storage.Therefore,accurate biomass estimation is essential for understanding ecosystem functioning and informing forest management strategies to mitigate climate change.However,integrating neighborhood competition into biomass estimation models,particularly for young mixed forest stands,remains unexplored.In this study,we examined how incorporating neighborhood competition improves biomass prediction accuracy and how the influence of neighborhood competition differs between Scots pine(Pinus sylvestris L.)and Pyrenean oak(Quercus pyrenaica Willd.),as well as the relative contributions of intra-and interspecific competition to AGB.Our findings revealed that including neighborhood competition alongside tree size variables(DBH and total tree height)significantly improved the predictive accuracy of AGB models for Scots pine.This addition reduced the root mean square error(RMSE)by 14% and improved the model efficiency factor(MEF)by 15%.Furthermore,intraspecific competition in Scots pine slightly reduced AGB,whereas interspecific competition had a significant negative effect on AGB.In contrast,DBH alone was the best predictor of AGB for Pyrenean oak,as neighborhood competition did not improve model performance.Also,intra-and interspecific competition in Pyrenean oak had positive but nonsignificant effects on AGB.These findings highlight the important role of competition in biomass models and suggest species-specific approaches in competition dynamics to inform sustainable forest management and climate change adaptation strategies.展开更多
Sessile oak(Quercus petraea(Matt.)Liebl.)is widely distributed across most of Europe particularly the hills and lower mountain ranges,so is considered“the oak of the mountains”.This species grows on a wide variety o...Sessile oak(Quercus petraea(Matt.)Liebl.)is widely distributed across most of Europe particularly the hills and lower mountain ranges,so is considered“the oak of the mountains”.This species grows on a wide variety of soils and at altitudes ranging from sea level to 2200 m,especially in Atlantic and sub-Mediterranean climates,and it is sensitive to low winter temperatures,early and late frosts,as well as high summer temperatures.Sessile oak forms both pure and mixed stands especially with broadleaves such as European beech,European hornbeam,small-leaved lime and Acer spp.These form the understorey of sessile oak stands,promoting the natural shedding of lower branches of the oak and protecting the trunk against epicormic branches.Sessile oak is a long-lived,light-demanding and wind-firm species,owing to its taproot and heart-shaped root system.Its timber,one of the most valuable in Europe,is important for fur-niture-making(both solid wood and veneer),construction,barrels,railway sleepers,and is also used as fuelwood.It is one of the few major tree species in Europe that is regener-ated by seed(naturally or artificially)and by stump shoots in high forest,coppice-with-standards and coppice forests.Sessile oak forests are treated in both regular and irregular systems involving silvicultural techniques such as uniform shelterwood,group shelterwood,irregular shelterwood,irregular high forest,coppice-with-standards and simple coppice.Young naturally regenerated stands are managed by weeding,release cutting and cleaning-respacing,keeping the stands quite dense for good natural pruning.Plantations are based on(1)2-4-year old bare-root or container-grown seedlings produced in nurseries using seeds from genetic resources,seed stands and seed orchards.The density of sessile oak plantations(mostly in rows,but also in clusters)is usually between 4000 and 6000 ind.ha^(−1).Sessile oak silviculture of mature stands includes crown thinning,focus-ing on final crop trees(usually a maximum of 100 ind.ha^(−1))and targeting the production of large-diameter and high quality trees at long rotation ages(mostly over 120 years,sometimes 250-300 years).In different parts of Europe,conversion of simple coppices and coppice-with-standards to high forests is continuing.Even though manage-ment of sessile oak forests is very intensive and expensive,requiring active human intervention,the importance of this species in future European forests will increase in the con-text of climate change due to its high resistance to distur-bance,superior drought tolerance and heat stress resistance.展开更多
Background： With mounting global environmental, social and economic pressures the resilience and stability of forests and thus the provisioning of vital ecosystem services is increasingly threatened. Intensified moni...Background： With mounting global environmental, social and economic pressures the resilience and stability of forests and thus the provisioning of vital ecosystem services is increasingly threatened. Intensified monitoring can help to detect ecological threats and changes earlier, but monitoring resources are limited. Participatory forest monitoring with the help of ＂citizen scientists＂ can provide additional resources for forest monitoring and at the same time help to communicate with stakeholders and the general public. Examples for citizen science projects in the forestry domain can be found but a solid, applicable larger framework to utilise public participation in the area of forest monitoring seems to be lacking. We propose that a better understanding of shared and related topics in citizen science and forest monitoring might be a first step towards such a framework. Methods： We conduct a systematic meta-analysis of 1015 publication abstracts addressing ＂forest monitoring＂ and ＂citizen science＂ in order to explore the combined topical landscape of these subjects. We employ ＇topic modelling an unsupervised probabilistic machine learning method, to identify latent shared topics in the analysed publications. Results： We find that large shared topics exist, but that these are primarily topics that would be expected in scientific publications in general. Common domain-specific topics are under-represented and indicate a topical separation of the two document sets on ＂forest monitoring＂ and ＂citizen science＂ and thus the represented domains. While topic modelling as a method proves to be a scalable and useful analytical tool, we propose that our approach could deliver even more useful data if a larger document set and full-text publications would be available for analysis. Conclusions： We propose that these results, together with the observation of non-shared but related topics, point at under-utilised opportunities for public participation in forest monitoring. Citizen science could be applied as a versatile tool in forest ecosystems monitoring, complementing traditional forest monitoring programmes, assisting early threat recognition and helping to connect forest management with the general public. We conclude that our presented approach should be pursued further as it may aid the understanding and setup of citizen science efforts in the forest monitoring domain.展开更多
Primary forests are spatially diverse terrestrial ecosystems with unique characteristics,being naturally regenerative and heterogeneous,which supports the stability of their carbon storage through the accumulation of ...Primary forests are spatially diverse terrestrial ecosystems with unique characteristics,being naturally regenerative and heterogeneous,which supports the stability of their carbon storage through the accumulation of live and dead biomass.Yet,little is known about the interactions between biomass stocks,tree genus diversity and structure across a temperate montane primary forest.Here,we investigated the relationship between tree structure(variability in basal area and tree size),genus-level diversity(abundance,tree diversity)and biomass stocks in temperate primary mountain forests across Central and Eastern Europe.We used inventory data from726 permanent sample plots from mixed beech and spruce across the Carpathian Mountains.We used nonlinear regression to analyse the spatial variability in forest biomass,structure,and genus-level diversity and how they interact with plot-level tree age,disturbances,temperature and altitude.We found that the combined effects of genus and structural indices were important for addressing the variability in biomass across different spatial scales.Local processes in disturbance regimes and uneven tree age support forest hete rogeneity and the accumulation of live and dead biomass through the natural regeneration,growth and decay of the forest ecosystem.Structural complexities in basal area index,supporte d by genus-level abundance,positively influence total biomass stocks,which was modulated by tree age and disturbances.Spruce forests showed higher tree density and basal area than mixed beech forests,though mixed beech still contributes significantly to biomass across landscapes.Forest heterogeneity was strongly influenced by complexities in forest composition(tree genus diversity,structure).We addressed the importance of primary forests as stable carbon stores,achieved through structure and diversity.Safeguarding such ecosystems is critical for ensuring the stability of the primary forest,carbon store and biodiversity into the future.展开更多
Spruce-dominated forests are commonly exposed to disturbances associated with mass occurrences of bark beetles.The dieback of trees triggers many physical and chemical processes in the ecosystem resulting in rapid cha...Spruce-dominated forests are commonly exposed to disturbances associated with mass occurrences of bark beetles.The dieback of trees triggers many physical and chemical processes in the ecosystem resulting in rapid changes in the vegetation of the lower forest layers.We aimed to determine the response of non-tree understory vegetation to the mass dieback of Norway spruce(Picea abies)in the first years after the disturbance caused by the European spruce bark beetle(Ips typographus)outbreak.Our study area was the Białowieża Biosphere Reserve covering the Polish part of the emblematic Białowieża Forest,in total 597km^(2).The main data source comprised 3,900 phytosociological relevés(combined spring and summer campaigns)collected from 1,300 systematically distributed forest sites in 2016–2018–the peak years of the bark beetle outbreak.We found that the understory responded immediately to mass spruce dieback,with the most pronounced changes observed in the year of the disturbance and the subsequent year.Shade-tolerant forest species declined in the initial years following the mass spruce dieback,while hemicryptophytes,therophytes,light-demanding species associated with non-forest seminatural communities,as well as water-demanding forest species,expanded.Oxalis acetosella,the most common understory species in the Białowieża Forest,showed a distinct fluctuation pattern,with strong short-term expansion right after spruce dieback,followed by a gradual decline over the next 3–4 years to a cover level 5 percentage points lower than before the disturbance.Thus,our study revealed that mass spruce dieback selectively affects individual herb species,and their responses can be directional and non-directional(fluctuation).Furthermore,we demonstrated that the mass dieback of spruce temporarily increases plant species diversity(α-diversity).展开更多
The combined use of LiDAR(Light Detection And Ranging)scanning and field inventories can provide spatially continuous wall-to-wall information on forest characteristics.This information can be used in many ways in for...The combined use of LiDAR(Light Detection And Ranging)scanning and field inventories can provide spatially continuous wall-to-wall information on forest characteristics.This information can be used in many ways in forest mapping,scenario analyses,and forest manage-ment planning.This study aimed to find the optimal way to obtain continuous forest data for Catalonia when using kNN imputation(kNN stands for“k nearest neighbors”).In this method,data are imputed to a certain location from k field-measured sample plots,which are the most similar to the location in terms of LiDAR metrics and topographic variables.Weighted multidimensional Euclidean distance was used as the similarity measure.The study tested two different methods to optimize the distance measure.The first method optimized,in the first step,the set of LiDAR and topographic variables used in the measure,as well as the transformations of these variables.The weights of the selected variables were optimized in the second step.The other method optimized the variable set as well as their transformations and weights in one single step.The two-step method that first finds the variables and their transfor-mations and subsequently optimizes their weights resulted in the best imputation results.In the study area,the use of three to five nearest neighbors was recommended.Altitude and latitude turned out to be the most important variables when assessing the similarity of two locations of Catalan forests in the context of kNN data imputation.The optimal distance measure always included both LiDAR metrics and topographic variables.The study showed that the optimal similarity measure may be different for different regions.Therefore,it was suggested that kNN data imputation should always be started with the optimization of the measure that is used to select the k nearest neighbors.展开更多
Environmental conditions can change markedly over geographical distances along elevation gradients,making them natural laboratories to study the processes that structure communities.This work aimed to assess the influ...Environmental conditions can change markedly over geographical distances along elevation gradients,making them natural laboratories to study the processes that structure communities.This work aimed to assess the influences of elevation on Tropical Montane Cloud Forest plant communities in the Brazilian Atlantic Forest,a historically neglected ecoregion.We evaluated the phylogenetic structure,forest structure(tree basal area and tree density)and species richness along an elevation gradient,as well as the evolutionary fingerprints of elevation-success on phylogenetic lineages from the tree communities.To do so,we assessed nine communities along an elevation gradient from 1210 to 2310 m a.s.l.without large elevation gaps.The relationships between elevation and phylogenetic structure,forest structure and species richness were investigated through Linear Models.The occurrence of evolutionary fingerprint on phylogenetic lineages was investigated by quantifying the extent of phylogenetic signal of elevation-success using a genus-level molecular phylogeny.Our results showed decreased species richness at higher elevations and independence between forest structure,phylogenetic structure and elevation.We also verified that there is a phylogenetic signal associated with elevation-success by lineages.We concluded that the elevation is associated with species richness and the occurrence of phylogenetic lineages in the tree communities evaluated in Mantiqueira Range.On the other hand,elevation is not associated with forest structure or phylogenetic structure.Furthermore,closely related taxa tend to have their higher ecological success in similar elevations.Finally,we highlight the fragility of the tropical montane cloud forests in the Mantiqueira Range in face of environmental changes(i.e.global warming)due to the occurrence of exclusive phylogenetic lineages evolutionarily adapted to environmental conditions(i.e.minimum temperature)associated with each elevation range.展开更多
Arbuscular mycorrhizal fungi(AMF)play a vital role in plant productivity and ecosystem functions.However,their responses to abiotic factors(i.e.,climate,physiography,and soil properties)are unknown,especially across c...Arbuscular mycorrhizal fungi(AMF)play a vital role in plant productivity and ecosystem functions.However,their responses to abiotic factors(i.e.,climate,physiography,and soil properties)are unknown,especially across climatic gradients and slope aspects in arid and semi-arid ecosys-tems.In this study,using 60 composite soil samples,direct and indirect effects of climate factors and slope aspects on AMF diversity,composition and spore density were studied.The findings indicate that climate has a more direct influ-ence on soil properties(P<0.001)in comparison to slope aspect(P=0.449).In contrast,climate significantly affected AMF diversity and composition,with the highest diversity in dryer areas.Soil pH had the highest correlation with different facets of AMF diversity.Structural equation modeling(SEM)indicated that only a small part of the variation in AMF diversity and spore density could be explained by climate characteristics,slope aspect and soil properties.Based on SEM results,climate was the most important determinant of AMF diversity and spore density;slope aspect had a less critical role.The outputs suggest that variations in AMF diversity are derived by the direct effects of climate and the indirect effect of soil chemical properties.In addition,with increasing dryness,sporulation and AMF diversity increased.展开更多
Understanding how past disturbances have influenced the development of forests is critical for deciphering their current structure and composition and forecasting future changes.In this study,dendrochronological metho...Understanding how past disturbances have influenced the development of forests is critical for deciphering their current structure and composition and forecasting future changes.In this study,dendrochronological methods were applied to uncover the disturbance history of old-growth hemlock-dominated forests in central Bhutan.Analysis of tree-ring samples from two old-growth hemlock stands,located in two different topographic settings,identified the importance of gap-phase dynamics in facilitating recruitment and growth releases and producing complex,multi-aged structure s over time.One site showed evidence of a near stand-replacing disturbance in the late 1700s,while the other showed no evide nce of high-severity disturbance at any time over the last 400 years.At both sites low-to medium-severity disturbances,some of which appear to be associated with cyclones originating in the Bay of Bengal,dominated the disturbance regime.The hemlock stands exhibited a significant positive association between cyclone occurrence and growth release events and between recruitment pulses and growth release events.From 1800 to 1970 there was an increase in recruitment of angiosperm tree species at most sites and a corresponding decline in conifer recruitment.Over the past 50 years there has been little new recruitment;this may be due to light limitation in the understory from shade-tolerant angiosperms and bamboo in the lower strata of these stands.Significant variations in disturbance dynamics and recruitment were observed across the study sites,suggesting that other factors,such as topography and climate,may be influencing long-term stand development patterns.This study highlights the complex interplay between historical disturbance regimes and tree recruitment in shaping the age and size structures of old-growth hemlock forests in central Bhutan.It also provides new insights into the dynamics of these forests that can be used to support effective forest conservation and management in the future.展开更多
In Central Europe,anthropogenic coniferous monocultures have been subject to conversion to more diverse mixed forests since the 1990s,however,they are still abundant across many forest landscapes.Artificial and natura...In Central Europe,anthropogenic coniferous monocultures have been subject to conversion to more diverse mixed forests since the 1990s,however,they are still abundant across many forest landscapes.Artificial and natural tree regeneration both play a key role during conversion by determining the species composition and structure of the future forests.Many abiotic and biotic factors can potentially influence the regeneration process and its specific combinations or interactions may be different among tree species and its developmental stages.Here,we aimed to identify and quantify the effect of the most important drivers on the density of the most abundant regenerating tree species(i.e.,Norway spruce and European beech),as well as on species and structural diversity of the tree regeneration.We studied tree regeneration in four former monospecific coniferous stand types(i.e.,Norway spruce,Scots pine,European larch,and Douglas fir)in Southwest Germany that have been under conversion to mixed forests since the 1990s.We sampled tree regeneration in four growth height classes together with a variety of potentially influencing factors on 108 sampling plots and applied multivariate analyses.We identified light availability in the understorey,stand structural attributes,browsing pressure,and diaspore source abundance as the most important factors for the density and diversity of tree regeneration.Particularly,we revealed speciesspecific differences in drivers of regeneration density.While spruce profited from increasing light availability and decreasing stand basal area,beech benefited either from a minor reduction or more strikingly from an increase in overstorey density.Increasing diaspore source abundance positively and a high browsing pressure negatively affected both species equally.Our results suggest that humus and topsoil properties were modified during conversion,probably due to changes in tree species composition and silvicultural activities.The species and structural diversity of the tree regeneration benefitted from increasing light availability,decreasing stand basal area,and a low to moderate browsing pressure.We conclude that forest managers may carefully equilibrate among the regulation of overstorey cover,stand basal area,and browsing pressure to fulfil the objectives of forest conversion,i.e.,establishing and safeguarding a diverse tree regeneration to promote the development of mature mixed forests in the future.展开更多
Multispecies forests have received increased scientific attention,driven by the hypothesis that biodiversity improves ecological resilience.However,a greater species diversity presents challenges for forest management...Multispecies forests have received increased scientific attention,driven by the hypothesis that biodiversity improves ecological resilience.However,a greater species diversity presents challenges for forest management and research.Our study aims to develop basal area growth models for tree species cohorts.The analysis is based on a dataset of 423 permanent plots(2,500 m^(2))located in temperate forests in Durango,Mexico.First,we define tree species cohorts based on individual and neighborhood-based variables using a combination of principal component and cluster analyses.Then,we estimate the basal area increment of each cohort through the generalized additive model to describe the effect of tree size,competition,stand density and site quality.The principal component and cluster analyses assign a total of 37 tree species to eight cohorts that differed primarily with regard to the distribution of tree size and vertical position within the community.The generalized additive models provide satisfactory estimates of tree growth for the species cohorts,explaining between 19 and 53 percent of the total variation of basal area increment,and highlight the following results:i)most cohorts show a"rise-and-fall"effect of tree size on tree growth;ii)surprisingly,the competition index"basal area of larger trees"had showed a positive effect in four of the eight cohorts;iii)stand density had a negative effect on basal area increment,though the effect was minor in medium-and high-density stands,and iv)basal area growth was positively correlated with site quality except for an oak cohort.The developed species cohorts and growth models provide insight into their particular ecological features and growth patterns that may support the development of sustainable management strategies for temperate multispecies forests.展开更多
文摘Forests play a vital role in mitigating climate change through their physiological functions and metabolic processes,including their ability to convert solar energy into biomolecules.However,further research is necessary to elucidate how structural characteristics of a forest and topographic settings influence energy conversion and surface temperature of a forest.In this study,we investigated a beech forest in central Germany using airborne laser scanning(ALS)point cloud data and land surface temperature(LST)data derived from Landsat 9 satellite imagery.We constructed 30 m×30 m plots across the study area(approximately 17 km2)to align the spatial resolution of the satellite imagery with the ALS data.We analyzed topographic variables(surface elevation,aspect and slope),forest attributes(canopy cover,canopy height,and woody area index),as well as forest structural complexity,quantified by the box-dimension(Db).Our analysis revealed that LST is significantly influenced by both forest attributes and topographic variables.A multiple linear regression model demonstrated an inverse relationship(R^(2)=0.38,AIC=8105)between LST and a combination of Db,elevation,slope,and aspect.However,the model residuals exhibited significant spatial dependency,as indicated by Moran’s I test.To address this,we applied a spatial autoregressive model,which effectively accounted for spatial autocorrelation and improved the model fit(AIC=746).Our findings indicate that elevation exerts the most substantial influence on LST,followed by forest structural complexity,slope,and aspect.We conclude that forest management practices that enhance structural complexity can effectively reduce land surface temperatures in forested landscapes.
基金supported by the Swedish Government Research Council for Sustainable Development(Formas)grant#2023-00994.
文摘Background: Continuous Cover Forestry(CCF) is a type of forest management that is based on ecological, environmental, and biological principles. Specific definitions of CCF greatly vary and the concept usually includes a number of tenets or criteria. The most important tenet of CCF is the requirement to abandon the practice of largescale clearfelling in favour of selective thinning/harvesting and natural regeneration methods.Methods: CCF is commonly believed to have its main origin in an academic debate that was conducted through publications in a number of European and North American countries towards the end of the 19th and the beginning of the 20th century. Our findings are exclusively based on a literature review of the history of CCF and they revealed that the European origins of CCF go much further back to a form of farm forestry that started to be practised in Central Europe in the 17th century. Eventually, this type of farm forestry led to the formation of the single-tree selection system as we know it today. Another influential tradition line contributing to modern CCF is individual-based forest management, which breaks forest stands down into small neighbourhood-based units. The centres of these units are dominant frame trees which form the framework of a forest stand. Consequently, management is only carried out in the local neighbourhood of frame trees. Individual-based forest management also modified inflexible area-control approaches of plantation forest management in favour of the flexible sizecontrol method.Results and conclusions: We found evidence that the three aforementioned tradition lines are equally important and much interacted in shaping modern CCF. Since CCF is an international accomplishment, it is helpful to thoroughly study the drivers and causes of such concepts. Understanding the gradual evolution can give valuable clues for the introduction and adaptation of CCF in countries where the concept is new.
基金financial support provided by the German Research Foundation,DFG,through grant number KL894/23-2 and NO 1444/1-2 as part of the Research Unit FOR2432/2the China Scholarship Council(CSC)that supports the first author with a Ph D scholarshipsupport provided by Indian partners at the Institute of Wood Science and Technology(IWST),Bengaluru。
文摘Rapid urbanization has caused significant changes along the urban-rural gradient,leading to a variety of landscapes that are mainly shaped by human activities.This dynamic interplay also influences the distribution and characteristics of trees outside forests(TOF).Understanding the pattern of these trees will support informed decision-making in urban planning,in conservation strategies,and altogether in sustainable land management practices in the urban context.In this study,we employed a deep learning-based object detection model and high resolution satellite imagery to identify 1.3 million trees with bounding boxes within a 250 km^(2)research transect spanning the urban-rural gradient of Bengaluru,a megacity in Southern India.Additionally,we developed an allometric equation to estimate diameter at breast height(DBH)from the tree crown diameter(CD)derived from the detected bounding boxes.Our study focused on analyzing variations in tree density and tree size along this gradient.The findings revealed distinct patterns:the urban domain displayed larger tree crown diameters(mean:8.87 m)and DBH(mean:43.78 cm)but having relatively low tree density(32 trees per hectare).Furthermore,with increasing distance from the city center,tree density increased,while the mean tree crown diameter and mean tree basal area decreased,showing clear differences of tree density and size between the urban and rural domains in Bengaluru.This study offers an efficient methodology that helps generating instructive insights into the dynamics of TOF along the urban-rural gradient.This may inform urban planning and management strategies for enhancing green infrastructure and biodiversity conservation in rapidly urbanizing cities like Bengaluru.
基金funded by Gorgan University of Agricultural Sciences and Natural Resources(grant number 9318124503).
文摘Plant species diversity is one of the most widely used indicators in ecosystem management.The relation of species diversity with the size of the sample plot has not been fully determined for Oriental beech forests(Fagus orientalis Lipsky),a widespread species in the Hyrcanian region.Assessing the impacts of plot size on species diversity is fundamental for an ecosystem-based approach to forest management.This study determined the relation of species diversity and plot size by investigating species richness and abundance of both canopy and forest floor.Two hundred and fifty-six sample plots of 625 m^(2) each were layout in a grid pattern across 16 ha.Base plots(25 m×25 m)were integrated in different scales to investigate the effect of plot size on species diversity.The total included nine plots of 0.063,0.125,0.188,0.250,0.375,0.500,0.563,0.750 and 1 ha.Ten biodiversity indices were calculated.The results show that species richness in the different plot sizes was less than the actual value.The estimated value of the Simpson species diversity index was not significantly different from actual values for both canopy and forest floor diversity.The coefficient of variation of this index for the 1-ha sample plot showed the lowest amount across different plot sizes.Inverse Hill species diversity was insignificant difference across different plot sizes with an area greater than 0.500 ha.The modified Hill evenness index for the 1-ha sample size was a correct estimation of the 16-ha for both canopy and forest floor;however,the precision estimation was higher for the canopy layer.All plots greater than 0.250-ha provided an accurate estimation of the Camargo evenness index for forest floor species,but was inaccurate across different plot sizes for the canopy layer.The results indicate that the same plot size did not have the same effect across species diversity measurements.Our results show that correct estimation of species diversity measurements is related to the selection of appropriate indicators and plot size to increase the accuracy of the estimate so that the cost and time of biodiversity management may be reduced.
基金supported by the Italian Ministry of Agriculture,Ministry of Agriculture,Food Sovereignty and Forestry(MASAF),National program sub project Precision Forestry(AgriDigit program)(DM 36509.7305.2018 of 20/12/2018).
文摘Forest planning involves estimating the biomass of species present in the area.Two fundamental parameters are diameter and height through which it is possible to indirectly estimate of biomass present.Digitalisation of forestry operations,such as forest planning,is crucial and should be affordable and easy-to-use digital applications and open-source devices.A digital progressive web application(PWA)was designed to record measurements.The app was connected via bluetoot to an open-source IoT digital forestry caliper prototyped by modifying a commercial tree caliper.An economic analysis was carried out considering all costs necessary for the development and operation of the app on smartphones and the preparation of electronic means for creation of the digital caliper.A comparison was made between costs of detecting tree diameters through application of the technology developed compared to costs calculated by applying the use of a dendrometric caliper(three technological levels were considered:L1,L2 and L3).The PWA allowed for easy data entry and viewing,maps and tree densities.The open-source digital caliper showed accuracy and precision comparable with similar commercial devices(1.5%±0.9%and 0.0%±0.9%,respectively).Total time per operator was lower using the digital caliper.From an economic perspective,application of the digital technology was more sustainable than the traditional system.Use of the digital caliper in combination with the web application optimizes detection time of a single tree,and therefore decreases overall cost.
基金financially supported by the National Natural Science Foundation(No.32471868,No.32001324)Youth Lift Project of China Association for Science and Technology(No.YESS20210370)+1 种基金Fundamental Research Funds for the Central Universities(2572023CT01)We thank the Grassland Bureau and the National Innovation Alliance of Wildland Fire Prevention and Control Technology of China for supporting this research.
文摘Prescribed burning is commonly used to maintain forest ecosystem functions and reduce the risk of future wildfires.Although many studies have investigated the response of microbial community to wildfires in forest ecosystems,the effects of prescribed burnings on soil microbial community structure are less studied.It is also unclear that how post-fire soil physiochemical properties changes affected soil microbial communities.Here,we studied the impacts of prescribed burning on soil microbiome in three typical temperate forests of northern China by collecting soil physicochemical and high-throughput sequencing for 16S rRNA and 18S rRNA was applied to analyze the diversity and community composition of soil microbes(bacteria and fungi).Compared with pre-fire condition,prescribed burning significantly decreased Chaol index and altered soil bacterial communities(P<0.05),whereas it had no significant effect on fungal diversity and community structure of the(P>0.05).Planctomycetes and Actinobacteria made the greatest contributions to the bacterial community dissimilarity between the pre-fire and post-fire conditions.The main variables influencing the post-fire soil microbial community structure are soil pH,available phosphorus,total nitrogen,and the ratio of soil total carbon to soil total nitrogen,which could account for 73.5% of the variation in the microbial community structure in these stands.Our findings demonstrated a great discrepancy in the responses of bacteria and fungi to prescribed burning.Prescribed burning altered the soil microbial structure by modifying the physicochemical properties.Our results pointed that it is essential to evaluate the impact of prescribed burnings on forest ecosystem functions.These findings provide an important baseline for assessing post-fire microbial recovery in the region and offer critical guidance for restoration efforts.
文摘Forest ecosystems can be characterized by a set of catenas arranged along the slope in mountainous areas as these affect microhabitat features,which in turn influence soil properties.Heretofore,few studies have examined how topographic variables affect soil properties and quality in semiarid regions.This study aimed to provide important insights into how catena position and shape influence soil properties,soil quality,and their interrelationships in a semiarid protected oak forest in western Iran.Basic soil properties were measured in the laboratory.In addition,the soil quality index(SQI)was calculated at different topographic positions along both convex(Λ-shaped)and concave(V-shaped)catenas at two soil depths(0-15 and 15-30 cm).The findings indicated that soil organic carbon and total nitrogen declined in the lower depth in both V-andΛ-shaped catenas and at all catena positions.The lowest porosity was observed in the lower depth at toeslope positions(TS)of both catenas.Substrate-induced respiration(SIR),microbial biomass carbon(MBC),and basal respiration(BR)were higher in the upper depths at TS positions on V-shaped catenas than onΛ-shaped catenas.These biological indices were consistently higher in the upper depths than in the lower depths across all positions of both catenas.SQI had the highest values at TS positions on both catenas and in the upper depths across all positions.Pearson correlations between soil properties indicated that SQI was most strongly and positively correlated with biological properties in both catenas.The nutrient levels,microbial activity,and soil porosity in both catena shapes and at both soil depths displayed a relatively downward trend with increasing elevation from toeslope to summit positions.The results showed that catena topographic sequence shape and position affected most of the soil properties,providing evidence of the important role of topography in creating pedodiversity in oak forest ecosystems.
基金the Brazilian Coordination for the Improvement of Higher Education Personnel (CAPES) by granting the scholarship (Finance Code 001)supported by the Brazilian National Council for Scientific and Technological Development (CNPq, project number 433828/2018-8,435598/2018-0)+1 种基金the Minas Gerais Research Funding Foundation (FAPEMIG, project number CRA APQ 00929-15)CNPq productivity fellowships
文摘Functional traits are characteristics associated with the growth,reproduction,and survival of individuals.Studying them helps us understand how species traits drive ecosystem functioning.Thus,we evaluated the differences in traits and functional diversity between forest edges and interiors,and how the inclusion of intraspecific trait variation affects the assessment of functional diversity in these habitats.We sampled 10 representative forest patches,and,in each patch,we established five plots on the edge and five inside the forest,collecting leaf functional traits,allometric and wood density for all species.We assessed functional diversity using functional richness(FRic),divergence(FDiv),and dispersion(FDis).To assess the impact of incorporating intraspecific variation when comparing trait values and functional diversity indices,we established two scenarios:one that excludes intraspecific variation and another that includes it.We found that the edge and interior harbor individuals with distinct functional traits that alleviate the inherent stress of each habitat.The edge was also found to be more selective in terms of the range of functional traits,resulting in lower functional diversity.Our findings demonstrated that habitats play an important role in intraspecific trait variation(ITV)and that statistically significant differences between habitats,in relation to traits and functional diversity,were better observed with the inclusion of intraspecific variation.Our study highlights the potential of using natural forest patches to understand the edge effect,regardless of habitat loss.Additionally,we emphasize the importance of incorporating ITV into functional diversity studies,especially those on a smaller scale that incorporate quantitative variables,to better understand and predict ecological patterns.
基金funded by DGLP-General Directorate of the State Forest,Poland,in frame of the grant:“Changes in the carbon fixation potential of forest ecosystems in various regeneration scenarios after large-scale disturbances and stand decay in the context of climate protection and the role of forest management”,Agreement No.MZ.271.3.12.2023.University Grant No.BZ 4436/WL URK.
文摘Forest ecosystems are one of the largest terres-trial carbon(C)reservoirs on Earth and an important sink of anthropogenic CO_(2) emissions.Abiotic and biotic distur-bances such as windfalls,fires,outbreaks of insects or pests may negatively affect C storage in forest ecosystems decreas-ing their role as CO_(2) sink.The objective of this review was to summarize the current knowledge on the impact of large-scale forest ecosystem disturbances caused by windthrow and insect outbreaks on soil C stocks and cycles,and to gather information on the impact of restoration treatments performed in disturbed stands in the context of carbon accumulation in forest soils.Discussed were effects of wind-storms and insect outbreaks as well as impacts of various approaches of forest regeneration after disturbance on C stocks and fluxes.Disturbances decrease C stocks in forest ecosystems and turn them from C sink into C source for a certain time.Regeneration of the disturbed forest restores its role as a CO_(2) sink.In montane forests artificial afforestation seems to shorten the time of achieving C parity.However,no data exists for lowland forests.Hence,there is an urgent need for studies that assess effect of windfalls and insect outbreaks on carbon storage in forests of lowland Europe.
基金the 2019 call for the predoctoral contract at the University of Valladolid cofinanced by Banco de Santander and projects‘CLU-2019-01-Unidad de Excelencia Instituto iuFOR’,‘PID2021-126275OB-C21’and‘PID2021-126275OB-C22’-Integrated Forest Management along complexity gradients(IMFLEX)‘MCIN/AEI/10.13039/501100011033/FEDER,UE’,which received financial support from the Regional Government of Castilla and León,Spainthe European Regional Development Fund(ERDF).
文摘Neighborhood competition is a critical driver of individual tree growth,and aboveground biomass(AGB)accumulation,which together play key roles in forest dynamics and carbon storage.Therefore,accurate biomass estimation is essential for understanding ecosystem functioning and informing forest management strategies to mitigate climate change.However,integrating neighborhood competition into biomass estimation models,particularly for young mixed forest stands,remains unexplored.In this study,we examined how incorporating neighborhood competition improves biomass prediction accuracy and how the influence of neighborhood competition differs between Scots pine(Pinus sylvestris L.)and Pyrenean oak(Quercus pyrenaica Willd.),as well as the relative contributions of intra-and interspecific competition to AGB.Our findings revealed that including neighborhood competition alongside tree size variables(DBH and total tree height)significantly improved the predictive accuracy of AGB models for Scots pine.This addition reduced the root mean square error(RMSE)by 14% and improved the model efficiency factor(MEF)by 15%.Furthermore,intraspecific competition in Scots pine slightly reduced AGB,whereas interspecific competition had a significant negative effect on AGB.In contrast,DBH alone was the best predictor of AGB for Pyrenean oak,as neighborhood competition did not improve model performance.Also,intra-and interspecific competition in Pyrenean oak had positive but nonsignificant effects on AGB.These findings highlight the important role of competition in biomass models and suggest species-specific approaches in competition dynamics to inform sustainable forest management and climate change adaptation strategies.
文摘Sessile oak(Quercus petraea(Matt.)Liebl.)is widely distributed across most of Europe particularly the hills and lower mountain ranges,so is considered“the oak of the mountains”.This species grows on a wide variety of soils and at altitudes ranging from sea level to 2200 m,especially in Atlantic and sub-Mediterranean climates,and it is sensitive to low winter temperatures,early and late frosts,as well as high summer temperatures.Sessile oak forms both pure and mixed stands especially with broadleaves such as European beech,European hornbeam,small-leaved lime and Acer spp.These form the understorey of sessile oak stands,promoting the natural shedding of lower branches of the oak and protecting the trunk against epicormic branches.Sessile oak is a long-lived,light-demanding and wind-firm species,owing to its taproot and heart-shaped root system.Its timber,one of the most valuable in Europe,is important for fur-niture-making(both solid wood and veneer),construction,barrels,railway sleepers,and is also used as fuelwood.It is one of the few major tree species in Europe that is regener-ated by seed(naturally or artificially)and by stump shoots in high forest,coppice-with-standards and coppice forests.Sessile oak forests are treated in both regular and irregular systems involving silvicultural techniques such as uniform shelterwood,group shelterwood,irregular shelterwood,irregular high forest,coppice-with-standards and simple coppice.Young naturally regenerated stands are managed by weeding,release cutting and cleaning-respacing,keeping the stands quite dense for good natural pruning.Plantations are based on(1)2-4-year old bare-root or container-grown seedlings produced in nurseries using seeds from genetic resources,seed stands and seed orchards.The density of sessile oak plantations(mostly in rows,but also in clusters)is usually between 4000 and 6000 ind.ha^(−1).Sessile oak silviculture of mature stands includes crown thinning,focus-ing on final crop trees(usually a maximum of 100 ind.ha^(−1))and targeting the production of large-diameter and high quality trees at long rotation ages(mostly over 120 years,sometimes 250-300 years).In different parts of Europe,conversion of simple coppices and coppice-with-standards to high forests is continuing.Even though manage-ment of sessile oak forests is very intensive and expensive,requiring active human intervention,the importance of this species in future European forests will increase in the con-text of climate change due to its high resistance to distur-bance,superior drought tolerance and heat stress resistance.
文摘Background： With mounting global environmental, social and economic pressures the resilience and stability of forests and thus the provisioning of vital ecosystem services is increasingly threatened. Intensified monitoring can help to detect ecological threats and changes earlier, but monitoring resources are limited. Participatory forest monitoring with the help of ＂citizen scientists＂ can provide additional resources for forest monitoring and at the same time help to communicate with stakeholders and the general public. Examples for citizen science projects in the forestry domain can be found but a solid, applicable larger framework to utilise public participation in the area of forest monitoring seems to be lacking. We propose that a better understanding of shared and related topics in citizen science and forest monitoring might be a first step towards such a framework. Methods： We conduct a systematic meta-analysis of 1015 publication abstracts addressing ＂forest monitoring＂ and ＂citizen science＂ in order to explore the combined topical landscape of these subjects. We employ ＇topic modelling an unsupervised probabilistic machine learning method, to identify latent shared topics in the analysed publications. Results： We find that large shared topics exist, but that these are primarily topics that would be expected in scientific publications in general. Common domain-specific topics are under-represented and indicate a topical separation of the two document sets on ＂forest monitoring＂ and ＂citizen science＂ and thus the represented domains. While topic modelling as a method proves to be a scalable and useful analytical tool, we propose that our approach could deliver even more useful data if a larger document set and full-text publications would be available for analysis. Conclusions： We propose that these results, together with the observation of non-shared but related topics, point at under-utilised opportunities for public participation in forest monitoring. Citizen science could be applied as a versatile tool in forest ecosystems monitoring, complementing traditional forest monitoring programmes, assisting early threat recognition and helping to connect forest management with the general public. We conclude that our presented approach should be pursued further as it may aid the understanding and setup of citizen science efforts in the forest monitoring domain.
基金funded by the Czech University of Life Sciences Prague(Internal Grant Agency:A_03_22-43110/1312/3101)the Czech Science(GACR 21-27454S)。
文摘Primary forests are spatially diverse terrestrial ecosystems with unique characteristics,being naturally regenerative and heterogeneous,which supports the stability of their carbon storage through the accumulation of live and dead biomass.Yet,little is known about the interactions between biomass stocks,tree genus diversity and structure across a temperate montane primary forest.Here,we investigated the relationship between tree structure(variability in basal area and tree size),genus-level diversity(abundance,tree diversity)and biomass stocks in temperate primary mountain forests across Central and Eastern Europe.We used inventory data from726 permanent sample plots from mixed beech and spruce across the Carpathian Mountains.We used nonlinear regression to analyse the spatial variability in forest biomass,structure,and genus-level diversity and how they interact with plot-level tree age,disturbances,temperature and altitude.We found that the combined effects of genus and structural indices were important for addressing the variability in biomass across different spatial scales.Local processes in disturbance regimes and uneven tree age support forest hete rogeneity and the accumulation of live and dead biomass through the natural regeneration,growth and decay of the forest ecosystem.Structural complexities in basal area index,supporte d by genus-level abundance,positively influence total biomass stocks,which was modulated by tree age and disturbances.Spruce forests showed higher tree density and basal area than mixed beech forests,though mixed beech still contributes significantly to biomass across landscapes.Forest heterogeneity was strongly influenced by complexities in forest composition(tree genus diversity,structure).We addressed the importance of primary forests as stable carbon stores,achieved through structure and diversity.Safeguarding such ecosystems is critical for ensuring the stability of the primary forest,carbon store and biodiversity into the future.
文摘Spruce-dominated forests are commonly exposed to disturbances associated with mass occurrences of bark beetles.The dieback of trees triggers many physical and chemical processes in the ecosystem resulting in rapid changes in the vegetation of the lower forest layers.We aimed to determine the response of non-tree understory vegetation to the mass dieback of Norway spruce(Picea abies)in the first years after the disturbance caused by the European spruce bark beetle(Ips typographus)outbreak.Our study area was the Białowieża Biosphere Reserve covering the Polish part of the emblematic Białowieża Forest,in total 597km^(2).The main data source comprised 3,900 phytosociological relevés(combined spring and summer campaigns)collected from 1,300 systematically distributed forest sites in 2016–2018–the peak years of the bark beetle outbreak.We found that the understory responded immediately to mass spruce dieback,with the most pronounced changes observed in the year of the disturbance and the subsequent year.Shade-tolerant forest species declined in the initial years following the mass spruce dieback,while hemicryptophytes,therophytes,light-demanding species associated with non-forest seminatural communities,as well as water-demanding forest species,expanded.Oxalis acetosella,the most common understory species in the Białowieża Forest,showed a distinct fluctuation pattern,with strong short-term expansion right after spruce dieback,followed by a gradual decline over the next 3–4 years to a cover level 5 percentage points lower than before the disturbance.Thus,our study revealed that mass spruce dieback selectively affects individual herb species,and their responses can be directional and non-directional(fluctuation).Furthermore,we demonstrated that the mass dieback of spruce temporarily increases plant species diversity(α-diversity).
基金This work was supported by a Juan de la Cierva fellowship of the Spanish Ministry of Science and Innovation(FCJ2020-046387-I)the Spanish Ministry of Science,Innovation and Universities(PID2020-120355RB-IOO).
文摘The combined use of LiDAR(Light Detection And Ranging)scanning and field inventories can provide spatially continuous wall-to-wall information on forest characteristics.This information can be used in many ways in forest mapping,scenario analyses,and forest manage-ment planning.This study aimed to find the optimal way to obtain continuous forest data for Catalonia when using kNN imputation(kNN stands for“k nearest neighbors”).In this method,data are imputed to a certain location from k field-measured sample plots,which are the most similar to the location in terms of LiDAR metrics and topographic variables.Weighted multidimensional Euclidean distance was used as the similarity measure.The study tested two different methods to optimize the distance measure.The first method optimized,in the first step,the set of LiDAR and topographic variables used in the measure,as well as the transformations of these variables.The weights of the selected variables were optimized in the second step.The other method optimized the variable set as well as their transformations and weights in one single step.The two-step method that first finds the variables and their transfor-mations and subsequently optimizes their weights resulted in the best imputation results.In the study area,the use of three to five nearest neighbors was recommended.Altitude and latitude turned out to be the most important variables when assessing the similarity of two locations of Catalan forests in the context of kNN data imputation.The optimal distance measure always included both LiDAR metrics and topographic variables.The study showed that the optimal similarity measure may be different for different regions.Therefore,it was suggested that kNN data imputation should always be started with the optimization of the measure that is used to select the k nearest neighbors.
基金supported this work by granting the doctoral scholarship to Ravi Fernandes Mariano,Carolina Njaime Mendes and Cléber Rodrigo de Souza,and through the master’s scholarship to Aloysio Souza de Mourathe postdoctoral scholarship to Vanessa Leite Rezende+2 种基金The authors also thank the Conselho Nacional de Desenvolvimento Científico e Tecnológico(CNPQ)by project funding(Edital Universal 2014,Process 459739/2014-0)the Instituto Alto-Montana da Serra Fina,the Fundação de AmparoàPesquisa do Estado de Minas Gerais(FAPEMIG)the Fundação Grupo Boticário de ProteçãoàNatureza,and finally the Fundo de Recuperação,Proteção e Desenvolvimento Sustentável das Bacias Hidrográficas do Estado de Minas Gerais(Fhidro).
文摘Environmental conditions can change markedly over geographical distances along elevation gradients,making them natural laboratories to study the processes that structure communities.This work aimed to assess the influences of elevation on Tropical Montane Cloud Forest plant communities in the Brazilian Atlantic Forest,a historically neglected ecoregion.We evaluated the phylogenetic structure,forest structure(tree basal area and tree density)and species richness along an elevation gradient,as well as the evolutionary fingerprints of elevation-success on phylogenetic lineages from the tree communities.To do so,we assessed nine communities along an elevation gradient from 1210 to 2310 m a.s.l.without large elevation gaps.The relationships between elevation and phylogenetic structure,forest structure and species richness were investigated through Linear Models.The occurrence of evolutionary fingerprint on phylogenetic lineages was investigated by quantifying the extent of phylogenetic signal of elevation-success using a genus-level molecular phylogeny.Our results showed decreased species richness at higher elevations and independence between forest structure,phylogenetic structure and elevation.We also verified that there is a phylogenetic signal associated with elevation-success by lineages.We concluded that the elevation is associated with species richness and the occurrence of phylogenetic lineages in the tree communities evaluated in Mantiqueira Range.On the other hand,elevation is not associated with forest structure or phylogenetic structure.Furthermore,closely related taxa tend to have their higher ecological success in similar elevations.Finally,we highlight the fragility of the tropical montane cloud forests in the Mantiqueira Range in face of environmental changes(i.e.global warming)due to the occurrence of exclusive phylogenetic lineages evolutionarily adapted to environmental conditions(i.e.minimum temperature)associated with each elevation range.
文摘Arbuscular mycorrhizal fungi(AMF)play a vital role in plant productivity and ecosystem functions.However,their responses to abiotic factors(i.e.,climate,physiography,and soil properties)are unknown,especially across climatic gradients and slope aspects in arid and semi-arid ecosys-tems.In this study,using 60 composite soil samples,direct and indirect effects of climate factors and slope aspects on AMF diversity,composition and spore density were studied.The findings indicate that climate has a more direct influ-ence on soil properties(P<0.001)in comparison to slope aspect(P=0.449).In contrast,climate significantly affected AMF diversity and composition,with the highest diversity in dryer areas.Soil pH had the highest correlation with different facets of AMF diversity.Structural equation modeling(SEM)indicated that only a small part of the variation in AMF diversity and spore density could be explained by climate characteristics,slope aspect and soil properties.Based on SEM results,climate was the most important determinant of AMF diversity and spore density;slope aspect had a less critical role.The outputs suggest that variations in AMF diversity are derived by the direct effects of climate and the indirect effect of soil chemical properties.In addition,with increasing dryness,sporulation and AMF diversity increased.
基金support by Melbourne International Research Scholarship (MIRS)。
文摘Understanding how past disturbances have influenced the development of forests is critical for deciphering their current structure and composition and forecasting future changes.In this study,dendrochronological methods were applied to uncover the disturbance history of old-growth hemlock-dominated forests in central Bhutan.Analysis of tree-ring samples from two old-growth hemlock stands,located in two different topographic settings,identified the importance of gap-phase dynamics in facilitating recruitment and growth releases and producing complex,multi-aged structure s over time.One site showed evidence of a near stand-replacing disturbance in the late 1700s,while the other showed no evide nce of high-severity disturbance at any time over the last 400 years.At both sites low-to medium-severity disturbances,some of which appear to be associated with cyclones originating in the Bay of Bengal,dominated the disturbance regime.The hemlock stands exhibited a significant positive association between cyclone occurrence and growth release events and between recruitment pulses and growth release events.From 1800 to 1970 there was an increase in recruitment of angiosperm tree species at most sites and a corresponding decline in conifer recruitment.Over the past 50 years there has been little new recruitment;this may be due to light limitation in the understory from shade-tolerant angiosperms and bamboo in the lower strata of these stands.Significant variations in disturbance dynamics and recruitment were observed across the study sites,suggesting that other factors,such as topography and climate,may be influencing long-term stand development patterns.This study highlights the complex interplay between historical disturbance regimes and tree recruitment in shaping the age and size structures of old-growth hemlock forests in central Bhutan.It also provides new insights into the dynamics of these forests that can be used to support effective forest conservation and management in the future.
基金funded by the Bavarian Ministry for Food,Agriculture and Forestry (Grant No.F053)support by the Open Access Publication Funds/transformative agreements of the Gottingen University
文摘In Central Europe,anthropogenic coniferous monocultures have been subject to conversion to more diverse mixed forests since the 1990s,however,they are still abundant across many forest landscapes.Artificial and natural tree regeneration both play a key role during conversion by determining the species composition and structure of the future forests.Many abiotic and biotic factors can potentially influence the regeneration process and its specific combinations or interactions may be different among tree species and its developmental stages.Here,we aimed to identify and quantify the effect of the most important drivers on the density of the most abundant regenerating tree species(i.e.,Norway spruce and European beech),as well as on species and structural diversity of the tree regeneration.We studied tree regeneration in four former monospecific coniferous stand types(i.e.,Norway spruce,Scots pine,European larch,and Douglas fir)in Southwest Germany that have been under conversion to mixed forests since the 1990s.We sampled tree regeneration in four growth height classes together with a variety of potentially influencing factors on 108 sampling plots and applied multivariate analyses.We identified light availability in the understorey,stand structural attributes,browsing pressure,and diaspore source abundance as the most important factors for the density and diversity of tree regeneration.Particularly,we revealed speciesspecific differences in drivers of regeneration density.While spruce profited from increasing light availability and decreasing stand basal area,beech benefited either from a minor reduction or more strikingly from an increase in overstorey density.Increasing diaspore source abundance positively and a high browsing pressure negatively affected both species equally.Our results suggest that humus and topsoil properties were modified during conversion,probably due to changes in tree species composition and silvicultural activities.The species and structural diversity of the tree regeneration benefitted from increasing light availability,decreasing stand basal area,and a low to moderate browsing pressure.We conclude that forest managers may carefully equilibrate among the regulation of overstorey cover,stand basal area,and browsing pressure to fulfil the objectives of forest conversion,i.e.,establishing and safeguarding a diverse tree regeneration to promote the development of mature mixed forests in the future.
基金The National Forestry Commission of Mexico and The Mexican National Council for Science and Technology(CONAFOR-CONACYT-115900)。
文摘Multispecies forests have received increased scientific attention,driven by the hypothesis that biodiversity improves ecological resilience.However,a greater species diversity presents challenges for forest management and research.Our study aims to develop basal area growth models for tree species cohorts.The analysis is based on a dataset of 423 permanent plots(2,500 m^(2))located in temperate forests in Durango,Mexico.First,we define tree species cohorts based on individual and neighborhood-based variables using a combination of principal component and cluster analyses.Then,we estimate the basal area increment of each cohort through the generalized additive model to describe the effect of tree size,competition,stand density and site quality.The principal component and cluster analyses assign a total of 37 tree species to eight cohorts that differed primarily with regard to the distribution of tree size and vertical position within the community.The generalized additive models provide satisfactory estimates of tree growth for the species cohorts,explaining between 19 and 53 percent of the total variation of basal area increment,and highlight the following results:i)most cohorts show a"rise-and-fall"effect of tree size on tree growth;ii)surprisingly,the competition index"basal area of larger trees"had showed a positive effect in four of the eight cohorts;iii)stand density had a negative effect on basal area increment,though the effect was minor in medium-and high-density stands,and iv)basal area growth was positively correlated with site quality except for an oak cohort.The developed species cohorts and growth models provide insight into their particular ecological features and growth patterns that may support the development of sustainable management strategies for temperate multispecies forests.
