#Forest & Deadwood #2020 – 2023 #Landscape structure #Ecosystem services #Synthesis #Tree species composition #Forest structure #Spatial scale #Disturbance #Drought stress #Beech #Spruce #Temporal scale #Species biodiversity #Tree-related microhabitats #Ecosystem processes #Resources #Time series #Cultivation #Land use #Management #Productivity

Forest structure (Core project)

Forest structure: Properties, structure and management of the forest experimental plots

Core project 6

Forests are characterized by a highly variable compositional and spatial structure being extremely important for various ecological processes and availability of resources and habitats. However, the specific structure of a forest stand is changed by stand development due to tree growth, ageing and competition, disturbances, and by forest management.

Picture: The photo shows a beech forest in winter where a hole-cutting operation has been carried out. In an open area in front of standing trees, one can see tree stumps and sawn tree trunks lying on top of each other.

Background

Silvicultural interventions may do both, homogenize or diversify stand structure. Therefore, the assessment of stand structure and its quantitative description are crucial for understanding the impact of forest management on biodiversity and ecosystem functioning.

The forests of the exploratories differ in respect to regeneration method employed, tree species mixture, developmental phase, age structure, layering and patchiness. The managed forests of the exploratories cover the entire spectrum from planted, even-aged, single-layered, monoculture stands of conifers (spruce or pine) via naturally regenerated, even-aged, single or double layered monoculture stands of broadleaves (beech or oak) of various developmental phases to even-aged man-made mixed forests and uneven-aged beech forests. Additionally, pure and mixed forests dominated by European beech which have been unmanaged since some decades are studied.

Goals

Within the framework of the exploratories, this project serves to provide quantitative data for all experimental plots on 1) attributes of forest structure, 2) changes in attributes of forest structure due to forest management and natural processes, 3) stand development and productivity, 4) type and magnitude of forest management interventions, 5) deadwood amount and composition, and 6) abundance of tree microhabitats. This information may serve as explanatory variables for all teams working on functional biodiversity at the level of specific species, functional groups or multidiversity.

Additionally, we will further develop existing approaches of quantifying forest management intensity in order to analyse the relationship between forest structure and land use intensity.

Since 2019, we are involved in the new forest gap experiment (FOX), to whose design, planning and implementation we substantially contributed.

Picture: The diagram shows information on the design of the FOX forest experiment. — Fig. 1 Design of the FOX - Forest Experiment.

Methods

Our work is strongly based on inventories. That is, we locate, count and measure the objects of interest, be it living trees, deadwood items or habitats. Repeated inventories serve to quantify temporal changes, like tree growth or deadwood accumulation. Additionally, we rely on terrestrial laser scanning.

Work packages

In this phase (6th phase, 2020 – 2023) we will:

Experimental plots – EPs

Conduct the 3^rd repeated large trees inventory
Conduct the 2^nd laser scanning inventory
Monitor browsing damage
Quantify forest growth, tree harvests and other causes of tree mortality
Quantify the dynamics of stand structure
quantify the dynamics of management intensity using SMI and ForMI indices

New forest gap experiment (FOX)

Document characteristics of deadwood logs
Sample deadwood logs by drilling
Monitor canopy closure by laser scanning
Monitor the root development in the canopy gap
Monitor tree regeneration

Services

All core projects provide important basic information on land use, diversity and ecosystem processes (long-term monitoring). This information is made available to all sub-projects and core projects for in depth research.

Services provided in the current phase (2020-2023)

In the 6th phase (2020-2023), the core project Forest Structure provides the following services/baseline studies. The corresponding data are stored in BExIS.

Experiment plots – EP

Annually resolved harvest quantities for all forest EPs
Annually resolved management intensity SMI for all forest EPs
Crown closure, forest structure measures and their dynamics from terrestrial laser scanning for all forest EPs
Stem maps with information on tree species and tree dimensions for all forest EPs
Stand characteristics, forest structure measures, tree species composition and their dynamics based on the 3rd forest inventory
Forest growth, harvests and natural mortality for the period between 2nd and 3rd forest inventory
Density and composition of tree regeneration for all forest EPs
Communicating and processing of BE data for international projects (Bottoms-Up, Global Forest Biodiversity Initiative).

New gorest gap experiment (FOX)

Stem maps with information on tree species and tree dimension for all FOX plots
Tree species, tree dimension and coordinates of experimentally logged trees
Stand characteristics, forest structure measures and tree species composition for all FOX plots
Size of the gap from terrestrial laser scanning for FOX G and GD plots
Origin and location of deadwood logs for FOX D and GD plots
Volume of deadwood logs placed on FOX D and GD plots
Density and composition of tree regeneration for all FOX plots
Biomass and composition of roots up to 30 cm depth

Service provided during past phases

The core forest structure project has been part of the Biodiversity Exploratories since 2014, 4th phase. In the 4th and 5th phases, the Forest Structure Core Project provided the following service deliverables/baseline surveys.

Harmonised forest typing
Stand age of all forest EPs
Canopy closure and forest structure measures based on aerial and terrestrial laser scanning.
Completion of the 1st forest inventory on 22 forest EPs
Stand characteristics, forest structure measures and tree species composition based on the 1st and 2nd forest inventories in the 2nd and 4th phases of the exploratories, respectively.
Density and composition of tree regeneration for all forest EPs
Forest growth, harvest and natural mortality for the period between 1st and 2nd forest inventory
Volume productivity of all forest EPs
Data on browsing damage of young plants
Deadwood volume and deadwood composition based on two deadwood inventories for all forest EPs
Microhabitat abundance and diversity for all forest Eps based on a microhabitat inventory
Forest management intensity measured by the SMI and ForMI indices and their dynamics for all forest EPs
Design of the FOX experiment
Forest inventory of the FOX plots
Planning of gap cutting and deadwood enrichment

Picture: The diagram shows information on the status and dynamics of land use intensity in the forest for various tree species. Measured with the Indize For M I.

Status and dynamics of land use intensity in the forest measured with the indices ForMI.

Status and dynamics of land use intensity in forests measured by SMI indices.

Results

We found that different management of forests, including set-aside of commercial forests, affects forest growth, forest structure and biodiversity differently. Some results were quite unexpected.

Our most important finding is the positive effect of diverse forest management on the biodiversity of forest landscapes. These positive effects on biodiversity are largely based on the different (environmental) conditions in forests created by different forest treatments, such as through different tree species compositions or different forest developmental phases (Ehbrecht et al. 2019), which each provide habitats for specific species communities. Diversity in forest management thus leads to biotic diversity (Ammer et al. 2017, Heinrichs et al. 2020).

For example, forest landscapes composed of pure beech and pine stands showed higher species richness than the respective monospecific landscapes and additionally than mixed beech-pine stands for plants and lichens (Heinrichs et al. 2019) and other species groups. The comparison of forest management systems showed that the heterogeneity between young and old developmental phases of even-aged forests (i.e. a system composed of several stands that differ in age, but whose trees within a stand are of the same age) is more important for the biodiversity of many species groups, such as birds, beetles, spiders, plants and lichens, than the small-scale heterogeneity in uneven-aged forests, i.e. forests in which trees of all ages are intensively mixed (Schall et al. 2018a). Forests set aside for only a few decades rarely contributed to the biotic enrichment of forest landscapes (e.g. deadwood fungi), while the bulk of species, the so-called multi-diversity, benefits from a high proportion of even-aged forests (see Fig 1, Schall et al. 2020). The low impact on biodiversity of forests set aside only recently is not that surprising, however, since these forests are usually still in the optimal growth phase with a high-volume production of 7 m³ ha^-1 year^-1, a completely closed canopy and a homogeneous vertical structure (Schall et al. 2018b). This uniformity will only dissolve over time or due of disturbances, thereby generating the diversity of abiotic conditions that is obviously promoting biodiversity.

The modulating effect of cutting interventions also appeared over time. Thus, managed forests showed no decrease in the diversity of arthropods, which was otherwise observed in forests as well as in grassland, only at higher levels of interventions (Seibold et al. 2019, Extended Data Fig. 4).

Fig. 3 Gamma multidiversity in % (a) and relative gamma diversity (b) of 14 taxonomic groups for forest landscapes with different proportions of even-aged (EA), uneven-aged (UEA) and unmanaged (UNM) forests.

Publications

Impacts of forest management on stand and landscape-level microclimate heterogeneity of European beech forests

Menge J. H., Magdon P., Wöllauer S., Ehbrecht M. (2023): Impacts of forest management on stand and landscape-level microclimate heterogeneity of European beech forests. Landscape Ecology 38, 903–917. doi: 10.1007/s10980-023-01596-z

Towards a causal understanding of the relationship between structural complexity, productivity, and adaptability of forests based on principles of thermodynamics

Seidel D., Ammer C. (2023): Towards a causal understanding of the relationship between structural complexity, productivity, and adaptability of forests based on principles of thermodynamics. Forest Ecology and Management 544, 121238. doi: 10.1016/j.foreco.2023.121238

Index of biodiversity potential (IBP) versus direct species monitoring in temperate forests

Zeller L., Baumann C., Gonin P., Heidrich L., Keye C., Konrad F., Larrieu L., Meyer P., Sennhenn-Reulen H., Müller J., Schall P., Ammer C. (2022): Index of biodiversity potential (IBP) versus direct species monitoring in temperate forests. Ecological Indicators 136: 108692. doi: 10.1016/j.ecolind.2022.108692

Short-term dynamics of structural complexity in differently managed and unmanaged European beech forests

Willim K., Ammer K., Seidel D., Annighöfer P., Schmucker J., Schall P., Ehbrecht M. (2022): Short-term dynamics of structural complexity in differently managed and unmanaged European beech forests. Trees, Forests and People 8, 100231. doi: 10.1016/j.tfp.2022.100231

Dispersal ability, trophic position and body size mediate species turnover processes: Insights from a multi‐taxa and multi‐scale approach

Bae S., Heidrich L., Levick S. R., Gossner M. M., Seibold S., Weisser W. W., Magdon P., Serebryanyk A., Bässler C., Schäfer D., Schulze E.-D., Doerfler I., Müller J., Jung K., Heurich M., Fischer M., Roth N., Schall P., Boch S., Wöllauer S., Renner S. C., Müller J. (2021): Dispersal ability, trophic position and body size mediate species turnover processes: Insights from a multi‐taxa and multi‐scale approach. Diversity and Distributions 27 (3), 439-453. doi: 10.1111/ddi.13204

On the structural complexity of central European agroforestry systems: a quantitative assessment using terrestrial laser scanning in single-scan mode

Seidel D., Stiers M., Ehbrecht M., Werning M., Annighöfer P. (2021): On the structural complexity of central European agroforestry systems: a quantitative assessment using terrestrial laser scanning in single-scan mode. Agroforestry systems 95, 669–685. doi: 10.1007/s10457-021-00620-y

Modelling the effects of forest management on landscape-level microclimate heterogeneity in European beech forests based on airborne laser scanning data (ALS)

Menge J. H. (2021): Modelling the effects of forest management on landscape-level microclimate heterogeneity in European beech forests based on airborne laser scanning data (ALS). Master thesis, University Göttingen

Among stand heterogeneity is key for biodiversity in managed beech forests but does not question the value of unmanaged forests: Response to Bruun and Heilmann-Clausen (2021)

Die Heterogenität der Bestände ist der Schlüssel für die biologische Vielfalt in bewirtschafteten Buchenwäldern, stellt aber den Wert unbewirtschafteter Wälder nicht in Frage: Antwort auf Bruun und Heilmann-Clausen (2021)

Schall P., Heinrichs S., Ammer C., Ayasse M., Boch S., Buscot F., Fischer M., Goldmann K., Overmann J., Schulze E.-D., Sikorski J., Weisser W. W., Wubet T., Gossner M. M. (2021): Among stand heterogeneity is key for biodiversity in managed beech forests but does not question the value of unmanaged forests: Response to Bruun and Heilmann-Clausen (2021). Journal of Applied Ecology 58 (9), 1817-1826. doi: 10.1111/1365-2664.13959

Effect of tree species mixing on stand structural complexity

Einfluss der Baumartenmischung auf die Komplexität der Bestandesstruktur

Juchheim J., Ehbrecht M., Schall P., Ammer C., Seidel D. (2020): Effect of tree species mixing on stand structural complexity. Forestry: An International Journal of Forest Research 93 (1), 75–83. doi: 10.1093/forestry/cpz046

Can multi‐taxa diversity in European beech forest landscapes be increased by combining different management systems?

Kann die Multitaxa-Biodiversität in europäischen Buchenwaldlandschaften durch die Kombination verschiedener Managementsysteme erhöht werden?

Schall P., Heinrichs S., Ammer C., Ayasse M., Boch S., Buscot F., Fischer M., Goldmann K., Overmann J., Schulze E.-D., Sikorski J., Weisser W. W., Wubet T., Gossner M. M. (2020): Can multi‐taxa diversity in European beech forest landscapes be increased by combining different management systems? Journal of Applied Ecology 57 (7), 1363-1375. doi: 10.1111/1365-2664.13635

Deriving stand structural complexity from airborne laser scanning data- What does it tells us about a forest?

Bestimmung der structurellen Bestandeskomplexität aus luftgestützen Laserscanningdaten- was sagt sie uns über den Wald?

Seidel D., Annighöfer P., Ehbrecht M., Magdon P., Wöllauer S., Ammer C. (2020): Deriving stand structural complexity from airborne laser scanning data - What does it tell us about a forest? Remote Sensing 12, 1854. doi: 10.3390/rs12111854

Dynamics of three-dimensional forest structure and canopy openness in European beech forests

Dynamik von dreidimensionaler Waldstruktur und Kronenbeschirmung in europäischen Buchenwäldern

Schmucker J. (2020): Dynamics of three-dimensional forest structure and canopy openness in European beech forests. Master thesis, University Göttingen

Annahmen und Ergebnisse zur Biodiversität im Wirtschafts- wald – Neues aus der Biodiversitätsforschung

Heinrichs S., Schall P., Ammer C., Fischer M., Gossner M. (2020): Annahmen und Ergebnisse zur Biodiversität im Wirtschaftswald – Neues aus der Biodiversitätsforschung. WSL-Berichte 100: 15-29.

Mapping forest tree species in high resolution UAV-based RGB-imagery by means of convolutional neural networks

Genaue Baumartenkartierung aus hochauflösenden UAV-basierten RGB-Bildern, ermöglicht durch neuronale Netzwerke

Schiefer F., Kattenborn T., Frick A., Frey J., Schall P., Koch B., Schmidtlein S. (2020): Mapping forest tree species in high resolution UAV-based RGB-imagery by means of convolutional neural networks. ISPRS Journal of Photogrammetry and Remote Sensing 170, 205-215. doi: 10.1016/j.isprsjprs.2020.10.015

Eignung des IBP (L’Indice de Biodiversité Potentielle) zur Abschätzung der Biodiversität in Wäldern – Eine empirische Studie anhand einer Erhebung in bewirtschafteten Wäldern in der Schwäbischen Alb

Eignung des IBP (L’Indice de Biodiversité Potentielle) zur Abschätzung der Biodiversität in Wäldern - Eine empirische Studie anhand einer Erhebung in bewirtschafteten Wäldern in der Schwäbischen Alb

Konrad F. (2020): Eignung des IBP (L’Indice de Biodiversité Potentielle) zur Abschätzung der Biodiversität in Wäldern - Eine empirische Studie anhand einer Erhebung in bewirtschafteten Wäldern in der Schwäbischen Alb. Bachelorarbeit, Universität Göttingen

Eignung des IBP (L’Indice de Biodiversité Potentielle) zur Abschätzung der Biodiversität in Wäldern. Eine Fallstudie auf Flächen der Biodiversitäts-Exploratorien in der Region Schorfheide-Chorin

Baumann C. (2020): Eignung des IBP (L’Indice de Biodiversité Potentielle) zur Abschätzung der Biodiversität in Wäldern. Eine Fallstudie auf Flächen der Biodiversitäts-Exploratorien in der Region Schorfheide-Chorin. Bachelorarbeit, Universität Göttingen

Scale-guided mapping of forest stand structural heterogeneity from airborne LiDAR

Kukunda C. B., Beckschäfer P., Magdon P., Schall P., Wirth C., Kleinn C. (2019): Scale-guided mapping of forest stand structural heterogeneity from airborne LiDAR. Ecological indicators 102, 410-425. doi: 10.1016/j.ecolind.2019.02.056

Analyzing the relationship between historic canopy dynamics and current plant species diversity in the herb layer of temperate forests using long-term Landsat time series

Graf W., Kleinn C., Schall P., Nauss T., Detsch T., Magdon P. (2019): Analyzing the relationship between historic canopy dynamics and current plant species diversity in the herb layer of temperate forests using long-term Landsat time series. Remote Sensing of Environment 232, 111305. doi: 10.1016/j.rse.2019.111305

Effects of structural heterogeneity on the diurnal temperature range in temperate forest ecosystems

Ehbrecht M., Schall P., Ammer C., Fischer M., Seidel D. (2019): Effects of structural heterogeneity on the diurnal temperature range in temperate forest ecosystems. Forest Ecology and Management 432, 860-867. doi: 10.1016/j.foreco.2018.10.008

Exclusion of large herbivores affects understorey shrub vegetation more than herb vegetation across 147 forest sites in three German regions

Wildausschluss beeinflusst Strauchvegetation stärker als Krautvegetation in 147 Waldflächen dreier deutscher Regionen

Schäfer D., Prati D., Schall P., Ammer C., Fischer M. (2019): Exclusion of large herbivores affects understorey shrub vegetation more than herb vegetation across 147 forest sites in three German regions. PLoS ONE 14(7): e0218741. doi: 10.1371/journal.pone.0218741

Landscape-Scale Mixtures of Tree Species are More Effective than Stand-Scale Mixtures for Biodiversity of Vascular Plants, Bryophytes and Lichens

Mischungen unterschiedlicher Reinbestände auf Landschaftsebene sind effektiver für die Biodiversität von Gefäßpflanzen, Moosen und Flechten als Mischbestände

Heinrichs S., Ammer C., Mund M., Boch S., Budde S., Fischer M., Müller J., Schöning I., Schulze E.-D., Schmidt W., Weckesser M., Schall P. (2019): Landscape-Scale Mixtures of Tree Species are More Effective than Stand-Scale Mixtures for Biodiversity of Vascular Plants, Bryophytes and Lichens. Forests 10 (1), 73. doi: 10.3390/f10010073

Response of Beech (Fagus sylvatica L.) Trees to Competition—New Insights from Using Fractal Analysis

Dorji Y., Annighöfer P., Ammer C. Seidel D. (2019): Response of Beech (Fagus sylvatica L.) Trees to Competition—New Insights from Using Fractal Analysis. Remote Sensing 11 (22), 2656. doi: 10.3390/rs11222656

The impact of even-aged and uneven-aged forest management on regional biodiversity of multiple taxa in European beech forests

Die Auswirkungen bestandesweiser und einzelbaumweiser Waldbewirtschaftung auf die regionale Artenvielfalt mehrerer Taxa in europäischen Buchenwäldern

Schall P., Gossner M. M., Heinrichs S., Fischer M., Boch S., Prati D., Jung K., Baumgartner V., Blaser S., Böhm S., Buscot F., Daniel R., Goldmann K., Kaiser K., Kahl T., Lange M., Müller J., Overmann J., Renner S., Schulze E.-D., Sikorski J., Tschapka M., Türke M., Weisser W. W., Wemheuer B., Wubet T., Ammer C. (2018): The impact of even-aged and uneven-aged forest management on regional biodiversity of multiple taxa in European beech forests. Journal of Applied Ecology 55 (1), 267–278. doi: 10.1111/1365-2664.12950

Relations between forest management, stand structure and productivity across different types of Central European forests

Beziehungen zwischen Waldbewirtschaftung, Bestandsstruktur und Produktivität in verschiedenen mitteleuropäischen Wäldern

Schall P., Schulze E.-D., Fischer M., Ayasse M., Ammer C. (2018): Relations between forest management, stand structure and productivity across different types of Central European forests. Basic and Applied Ecology 32, 39-52. doi: 10.1016/j.baae.2018.02.007

A holistic approach to determine tree structural complexity based on laser scanning data and fractal analysis

Eine holistischer Ansatz zur Bestimmung der strukturellen Komplexität von Bäumen

Seidel D. (2018): A holistic approach to determine tree structural complexity based on laser scanning data and fractal analysis. Ecology and Evolution 8 (1), 128–134. doi: 10.1002/ece3.3661. doi: 10.1002/ece3.3661

Applying fractal analysis to stem distribution maps

Fraktale analyse von Stammfußkarten

Seidel D., Annighöfer P., Ehbrecht M., Ammer C., Schall P. (2018): Applying fractal analysis to stem distribution maps. Ecological Indicators 93, 243-246. doi: 10.1016/j.ecolind.2018.05.016

Qualitative und quantitative Analyse der Totholzvorräte des Biodiversitäts-Exploratoriums Schwäbische Alb

Szemes D. G. C. A. (2018): Qualitative und quantitative Analyse der Totholzvorräte des Biodiversitäts-Exploratoriums Schwäbische Alb. Bachelor thesis, University Göttingen

Quantifying stand structural complexity and its relationship with forest management, tree species diversity and microclimate

Ehbrecht M., Schall P., Ammer C., Seidel D. (2017): Quantifying stand structural complexity and its relationship with forest management, tree species diversity and microclimate. Agricultural & Forest Meteorology 242, 1–9. doi: 10.1016/j.agrformet.2017.04.012

Buche in Mischbeständen bei Trockenheit weniger gestresst

Annighöfer P., Metz J., Schall P., Schulze E.-D., Ammer C. (2017): Buche in Mischbeständen bei Trockenheit weniger gestresst. Allgemeine Forst Zeitschrift/Der Wald 72 (17), 13-15

Waldbewirtschaftung und Biodiversität: Vielfalt ist gefrag

Ammer C., Schall P., Goßner M. M., Heinrichs S., Boch S., Prati D., Jung K., Baumgartner V., Blaser S., Böhm S., Buscot F., Daniel R., Goldmann K., Kaiser K., Kahl T., Lange M., Müller J., Overmann J., Renner S. C., Schulze E.-D., Sikorski J., Tschapka M., Türke M., Weisser W. W., Wemheuer B., Wubet T., Fischer M. (2017): Waldbewirtschaftung und Biodiversität: Vielfalt ist gefragt! Allgemeine Forst Zeitschrift/Der Wald 17, 20-25

Quantifying three-dimensional stand structure and its relationship with forest management and microclimate in temperate forest ecosystems

Ehbrecht M. A. (2017): Quantifying three-dimensional stand structure and its relationship with forest management and microclimate in temperate forest ecosystems. Dissertation, University Göttingen

Effective number of layers: A new measure for quantifying three-dimensional stand structure based on sampling with terrestrial LiDAR

Effektive Anzahl an Schichten: ein neues Maß zur Beschreibung der vertikalen Bestandesstruktur mithilfe terrestrischen Laserscannings

Ehbrecht M., Schall P., Juchheim J., Ammer C., Seidel D. (2016): Effective number of layers: A new measure for quantifying three-dimensional stand structure based on sampling with terrestrial LiDAR. Forest Ecology and Management 380, 212–223. doi: 10.1016/j.foreco.2016.09.003

The so-called core projects of the BE emerged from the site selection project and the establishment of the exploratories (2006-2008). Since 2008, they have been providing the infrastructure and collecting important basic information on land use, diversity and ecosystem processes (long-term monitoring) for all projects. In addition, they coordinate project-wide activities such as various large-scale experiments.