1,721,214 research outputs found
Effects of structural heterogeneity on the diurnal temperature range in temperate forest ecosystems
No full textThe microclimate in forest ecosystems can be altered by modifications of stand structure due to forest management or natural forest development. Current forest management practices in Central Europe and North America aim to promote structural heterogeneity and maintain forest canopy cover, which is known to be a major driver of forest microclimate. Here, we investigated the impacts of forest management and structural heterogeneity on the diurnal temperature range (DTR) in 128 managed forest stands in three climatically different locations (Swabian Alb, Hainich-Dün and Schorfheide-Chorin) in Central Europe. Increasing structural heterogeneity by promoting tree size diversity and differentiation increased vertical stratification and resulted in an impaired DTR during the vegetation period. Linear regression models with geographic location, elevation above sea level, canopy openness and measures of structural heterogeneity as explanatory variables explained 79.4–80.9% of variance in DTR. However, the overall effect of structural heterogeneity on DTR was small. Differences in DTR between plots of different main tree species could be attributed to differences in canopy openness and light transmission, whereas tree species diversity had no significant effect on DTR. Unmanaged forests were characterized by a significantly lower DTR than managed, even-aged forests. DTR in uneven-aged stands managed under single tree selection was comparable to unmanaged stands. Terrestrial laser scanning (TLS) derived measures of canopy openness and vertical structure allowed to explain 79.4% of variance in DTR considering geographic location and elevation, which can also be assessed by TLS with integrated GPS and an altimeter. We conclude that structural characteristics of forest stands other than canopy openness contribute marginally to variation in forest microclimate. However, the analyses of structure-microclimate analyses indicate that effects of stand structure on DTR might be more pronounced in regions with low precipitation during the vegetation period
RETRACTED ARTICLE: Quantifying forest stand management intensity in Central European forests
No full textAchieving structural heterogeneity and high multi-taxon biodiversity in managed forest ecosystems: a European review
No full textAbstract The European Biodiversity Strategy has set the key goal to maintain and promote biodiversity. Managed forests here play a key role, as they are among the most diverse ecosystems. To create biodiversity rich managed forest landscapes, we need a deep understanding on how management affects forest structure and subsequently habitat quality on the local and landscape level. However, to date a confusingly large amount of different terms for various management systems exist and it remains unclear how forest structure and composition affected by specific management systems affect biodiversity. Here, we first aim to clarify forest management systems terminology. Second, we link existing management systems with forest structure and review at European level how these structures affect local α-, as well as landscape-scale β- and γ-biodiversity. We found that research and derived management guidelines have a strong focus on local forest stand heterogeneity and related α-diversity, while ignoring the importance of landscape-scale heterogeneity and therefore β- and γ-diversity. Instead of promoting one management system as an all-in-one-solution, a diversity of different forest management systems seems the most promising way to create biodiversity rich forest landscapes. We finally discuss how a combination of different management systems might help to create structurally rich forest habitats and landscapes, simulating different successional stages and promoting species rich communities
Can land use intensity be reliably quantified by using a single self‐thinning relationship?
No full textHow to quantify forest management intensity in Central European forests
Full text linkExisting approaches for the assessment of forest management intensity lack a widely accepted, purely quantitative measure for ranking a set of forest stands along a gradient of management intensity. We have developed a silvicultural management intensity indicator (SMI) which combines three main characteristics of a given stand: tree species, stand age and aboveground, living and dead wooden biomass. Data on these three factors are used as input to represent the risk of stand loss, which is a function of tree species and stand age, and stand density, which is a function of the silvicultural regime, stand age and tree species. Consequently, the indicator consists of a risk component (SMIr) and a density component (SMId). We used SMI to rank traditional management of the main Central European tree species: Norway spruce (Picea abies [Karst.] L.), European beech (Fagus sylvatica L.), Scots pine (Pinus sylvestris L.), and oak (Quercus robur L. and Quercus petraea L.). By analysing SMI over their whole rotation period, we found the following ranking of management intensity: oak<beech<pine≪spruce. Additionally, we quantified the SMI of actual research plots of the German Biodiversity exploratories, which represent unmanaged and managed forest stands including conifer forests cultivated outside their natural range. SMI not only successfully separate managed from unmanaged forests, but also reflected the variability of forest management and stand properties across the entire sample and within the different management groups. We suggest using SMI to quantify silvicultual management intensity of stands differing in species composition, age, silvicultural system (even-aged vs. uneven-aged), thinning grade and stages of stand conversion from one stand type into another. Using SMI may facilitate the assessment of the impact of forest management intensity on biodiversity in temperate forests
Exclusion of large herbivores affects understorey shrub vegetation more than herb vegetation across 147 forest sites in three German regions
Full text linkBackgroundMany studies have analysed the effect of browsing by large herbivores on tree species but far fewer studies have studied their effect on understorey shrubs and herbs. Moreover, while many studies have shown that forest features and management intensity strongly influence understorey vegetation, the influence of such variation on the effect of large-herbivore exclusion is not known.This studyIn this study, we analysed changes of species richness, Shannon diversity, evenness and cover of understorey herbs and shrubs after excluding large herbivores for seven years on 147 forest sites, differing in management intensity and forest features, in three regions of Germany (Schwäbische Alb, Hainich-Dün, Schorfheide-Chorin). Further, we studied how the effect of large-herbivore exclusion on understorey vegetation was influenced by forest management intensity and several forest features.ResultsAs expected, exclusion of large herbivores resulted in highly variable results. Nevertheless, we found that large-herbivore exclusion significantly increased cover and Shannon diversity of shrub communities, while it did not affect herb communities. Forest management intensity did not influence the effect of large-herbivore exclusion while some forest features, most often relative conifer cover, did. In forests with high relative conifer cover, large-herbivore exclusion decreased species richness and cover of herbs and increased Shannon diversity of herbs and shrubs, while in forests with low relative conifer cover large-herbivore exclusion increased species richness and cover of herbs, and decreased Shannon diversity of herbs and shrubs.ConclusionWe suggest that browsing by large herbivores should be included when studying understorey shrub communities, however when studying understorey herb communities the effects of browsing are less general and depend on forest features.</div
Correction to: Climatic factors controlling stem growth of alien tree species at a mesic forest site: a multispecies approach
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Effective number of layers: A new measure for quantifying three-dimensional stand structure based on sampling with terrestrial LiDAR
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