Effect of forest management on forest structure and its influence on forest biodiversity in temperate forests of central Europe

Abstract: Forest structure influences biodiversity in various ways, as tree species diversity, stand age and wood debris create distinct habitats and resources for different species. However, the response of biodiversity to diverse forest structures is not always predictable, with some species showing strong reactions and others exhibiting weak or negative responses. This inconsistency in species observations is primarily due to the highly variable conditions of each case study, highlighting the intricate relationship between biodiversity and forest structure, while making generalization challenging. A baseline understanding of the main patterns expected under specific environmental conditions is required to evaluate, monitor, or manage forests effectively.

For this purpose, the second chapter compiles existing literature on biodiversity's response to forest structure, extracting correlation values between the two and calculating the effect size for each study. We then compare the effect size of this response across different taxa and predict the expected effect size of the forest structure's influence on biodiversity.

To gather data, we searched the web for relevant literature and extracted information from published papers. Biodiversity was measured regarding the species richness of fungi, birds, understory vegetation, and beetles. We selected tree forest structure indicators such as DBH, species richness, and deadwood volume. We compared the effect size of biodiversity response across different taxa and forest structure indicators, calculating the correlation effect size using the Fisher z transformed value. Furthermore, we analyzed the effect size of biodiversity response to forest structures for forest stands of varying ages. We compiled the predicted effect size of the response for each analyzed taxa concerning each forest structure indicator.

Our findings indicate that forest structure has a low predicted effect size on biodiversity. The effect size of each relationship between each taxon and forest structure indicator analyzed decreases over time, except for three cases: the deadwood effect size on fungi, tree species richness effect size on birds, and DBH effect size on beetles. No significant difference was observed in the effect size of any forest structure indicator on any of the studied taxa.

Modern ecological silviculture focuses on preserving old-growth elements, enhancing forest diversity, increasing forest resilience, and conserving biodiversity and other forest-related ecosystem services. As forest structures impact forest resilience and ecosystem services, practitioners must comprehend the effects of management actions and emerging forest processes on these structures. However, forest structure is influenced by the interplay between management and environmental conditions, making it challenging to distinguish between the effects of direct management and emergent forest architecture, which refers to the structure arising from natural growth processes and the lasting impact of previous management actions.

This study aims to distinguish the effects of direct management and emergent forest architecture on forest structural diversity. We compared the impact of stand-level characteristics under direct management with emergent forest architecture variables (those resulting from tree growth and local environmental interactions) to assess their influence on forest structural diversity in the Southwest German Black Forest. We examined management intervention parameters, such as the number and composition of tree species, density, deadwood accumulation, and tree-related microhabitats. Although influenced by natural conditions, the number of canopy layers, light conditions, and tree diameter at breast height (DBH) are also affected by forest management decisions that shape emergent forest architecture.

We measured forest structural diversity as the standard deviation of all these variables. Using latent variables in a structural equation model, we analyzed the relationships between direct forest management, emergent forest architecture, and forest structural diversity. We then divided the data to quantify forest management effects on younger and more mature forest stands based on tree DBH.

Our findings reveal that direct management has a more significant impact on forest structural diversity than the naturally occurring emergent forest architecture. The deliberate selection of broad-leaf tree species and tree-species composition led to increased overall forest diversity. Conversely, emergent forest architecture had a more substantial influence on the structural diversity in younger forest stands. The effective variation in the number of layers was more pronounced in young stands than in old stands but resulted from the most recent harvesting intervention. Additionally, we discovered that the past selection of broad-leaved tree species through direct management decisions significantly affects forest structural diversity in the mature forest subset.

Our research emphasizes the long-term influence of forest management on structural diversity. After the management intervention, tree species selection is crucial in fostering high forest structural diversity in temperate-managed forests.

The relationship between heterogeneity and diversity suggests that environments with more diversity can support more species due to the availability of niches and resources. However, some studies have found no significant or negative effects of heterogeneity on species richness. Overall, environmental conditions can also impact the number of species that coexist due to limited resources and the regional species pool for specific environmental conditions. Nevertheless, there is a lack of comparison across different taxa. Management significantly affects both mean environmental conditions and heterogeneity in temperate European forests. Therefore, understanding how diversity varies across different groups of organisms in response to forest characteristics could help improve management interventions for biodiversity conservation.

This study aims to investigate the influence of mean environmental conditions and environmental heterogeneity on the diversity of seven taxonomic groups in a temperate mountain forest area in the black forest. The analysis includes structural and composition variables, plot level heterogeneity, mean conditions, and landscape context. The study examines three aspects of biodiversity: species richness, Shannon diversity, and beta diversity, to account for species turnover between sites. The primary objectives are to determine if one group of environmental variables is more important than the others in explaining variation in biodiversity and if environmental conditions have a uniform influence across several taxonomic groups and aspects of biodiversity.

The study found that no single factor or group of factors shapes all aspects of biodiversity in temperate forests, let alone in the same way. Local mean environmental conditions mostly had negative effects on alpha diversity, while local heterogeneity had mostly positive effects, except for a negative relationship between stand structural complexity and Shannon diversity of beetle families. At the local scale, most variables only significantly affected one or two of the seven taxonomic groups.

This study highlights the need to define the specific aspect/part of biodiversity that is being studied or desired to be promoted and identify the specific factors and their interactions that influence it. The results provide an overview of which conditions and contexts are most promising to be explored further for specific groups.

Forests in northern latitudes play a vital role in maintaining ecosystem function and resilience, hosting numerous species. Understanding the drivers of biodiversity is critical for ensuring the sustainability of forest ecosystems. Forest structure features, such as deadwood, tree species diversity, and understory heterogeneity, are essential drivers of forest biodiversity. This study aims to evaluate and compare the transition points for forest structure variables (deadwood, tree species richness, vegetation heterogeneity) required to cause a change in the richness and diversity of lichen and macrofungal species of conservation concern in three different forest types in Sweden.

The analysis utilized survey data from 496 woodland key habitat plots (plots with high conservation value) in three forest types (mixed stand, spruce-dominated, and pine-dominated stands) across Sweden. The study examined how different forest structure variables relate to the species richness and abundance of lichens and macrofungi signal species.

Conditional inference trees were used to identify the primary forest structure variables that cause a significant partition for optimal and sub-optimal species of concern diversity. Confidence intervals were estimated at 95\% by bootstrapping the results. The study estimated the transition point for species of concern and a subset of red-listed species.

The results showed deadwood as the most robust predictor of species richness and diversity for lichens and macrofungi in pine and spruce forests. However, identifying any indicators of fungal biodiversity in mixed forests was impossible. The deadwood volume threshold for lichens and macrofungi in pine forests was lower than those estimated for the spruce forest. The threshold values found for red-listed species were relatively low compared to those reported for non-red-listed species of conservation concern. Tree species richness and vegetation heterogeneity showed no significant chang

Object Details

• Location: Deutsche Nationalbibliothek Frankfurt am Main
• Extent: Online-Ressource
• Language: Englisch
• Notes: Universität Freiburg, Dissertation, 2023

Classification and Topics

• Keyword: Wald ; Biodiversität ; Waldökosystem ; Artenreichtum ; Forstwirtschaft ; Forstpolitik ; Artenreichtum

Contributors, Places and Time

• Event: Veröffentlichung
• (where): Freiburg
• (who): Universität
• (when): 2024
• Creator: Landivar Albis, Carlos Miguel
• Contributor: Dormann, Carsten F. ; Dormann, Carsten F. ; Bauhus, Jürgen ; Albert-Ludwigs-Universität Freiburg. Abteilung für Biometrie und Umweltsystemanalyse ; Albert-Ludwigs-Universität Freiburg. Fakultät für Umwelt und Natürliche Ressourcen

Further information

• DOI: 10.6094/UNIFR/243205
• URN: urn:nbn:de:bsz:25-freidok-2432058
• Rights: Open Access; Der Zugriff auf das Objekt ist unbeschränkt möglich.
• Last update: 25.03.2025, 1:43 PM CET