Core project 6: Forest structure - Properties, structure and management of the forest experimental plots

 

Previous project phase (2014-2017)

Scientific investigators:

Prof. Dr. Christian Ammer

Dr. Peter Schall

Martin Ehbrecht

Karl-Heinz Heine

Andreas Parth

Michael Unger

(Uni Göttingen)

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. 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.

 

Research focus

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, and 4) type and magnitude of forest management interventions. 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.

 

Method

Attributes of forest structure of the experimental plots will be quantified based on the initial forest inventory conducted in the 2nd and 3rd phase of the Exploratories (78234 trees surveyed) and a repeated inventory (this phase), data from airborne laserscanning conducted in the 2nd phase of the Exploratories, and unique data from terrestrial laser-scanning (this phase of the Exploratories).
The repeated forest inventory six years after the initial survey will allow analysing changes in stand structure, to determine forest productivity and to assess forest development.

We will use the information of the continuous land use monitoring, especially the amount of harvested wood by thinnings and final cuttings, to asses type and magnitude of forest management at the stand scale.

 

Previous project phase (2011-2014)

Forest Diversity: Systematic Assessment of Forest Structure and Biodiversity Indicators

 

Scientific investigators:

Prof. Dr. Christoph Kleinn

Dr. Lutz Fehrmann

Dr. Rainer Schulz

Dr. Paul Magdon

(University Göttingen)

Based on a coherent network of sample plots distributed over the total forest area of the Exploratories forest mensurational variables as well as diversity indicators are assessed to estimate those target variables at landscape level.

Extension of the monitoring concept using a systematic grid of sample plots

To statistically ensure conclusions on the effects of different forest 
management intensities on biodiversity of forests on the scale level
of the Exploratories the existing forest inventory concept is extended.
The starting point in that context represents the implementation of a
long-term sample, plot and estimation design allowing to address the
variability of estimated parameters as well as the estimation accuracy. 
Forest mensurational variables, indicators of structure and biodiversity,
and variables addressing quantity and quality of regeneration and dead
wood are assessed. The systematic inventory design on the total forest
area of the Exploratories offers the possibility for repeated assessments
of the variables and by this allows for a continued estimation of forest
diversity development at landscape level.

Continuation of the inventory on Experimental Plots

Besides the area-wide sample based forest inventory also the assessments on the Experimental Plots (EPs and VIPs) will be continued. The latter plots stem from a ‘guided stratified selection’ that considered the plot membership concerning defined categories of landscape and management characteristics in the selection process. Thus their selection is optimised with regard to investigations of treatment effects on the plots (e.g. forest management intensities) and can provide important information on functions and processes acting on the plot areas. Under additional consideration of the systematic inventory it can be analysed to which extend the Experimental Plots are ‘representative’ for the target variable distributions at landscape level.     

Regionalisation

The regionalisation of essential indicator variables for forest biodiversity is realised based on the data of the systematic inventory. Target variables in that context are e.g. tree species, stand density and above-ground biomass. Remote sensing data (digital aerial photographs, RapidEye satellite images) play a central role in the derivation of area-wide estimations in form of maps of important biodiversity variables. The regionalisation provides information that also enables other projects to better explain relationships between management types (and intensities) and forest diversity.
 


Previous project phase (untill 2011)

Scientific investigators:

Prof. Dr. Ernst-Detlef Schulze (Emeritus)

(MPI for Biogeochemistry, Jena)

 

Based on the hypothesis, that diverse ecosystems should not only be more productive but also more resilient against climatic extremes, this sub-project has the aim

1. to make regional assessments of biomass, tree diversity and management as one main basis for selection of the experimental plots

2. to inventory the selected experimental plots with respect to tree and species distribution

Methods

forest inventory

experiments

-    fencing experiment in the forest

-    establishment of BELongDead