Quantifying the impact of forest management intensity and neighborhood diversity on individual tree shape and canopy space filling

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The intensity of silvicultural interventions and the identity of the tree species that are cultivated are two basic tools of forest management. They can be used in order to control the ecological and economical value of a forest stand under given environmental conditions and the prevailing management objectives. By affecting the dimension and shape of tree crowns and stems, silvicultural measures determine habitat quality and quantity for species of various taxa. In the past it was very difficult to assess the three-dimensional spatial structure of a forest. This was due to the general inaccessibility, size and complexity of the study object, especially if the canopy layer is also to be considered. As a result, our knowledge on the distinct changes in tree architecture due to silvicultural management intensity or different neighborhood diversities is still small, especially if the focus is on single tree attributes, e.g. branching pattern or crown deformations. Thus, the suggested project will use unique spatial information on tree dimensions obtained from terrestrial laser scanning to determine the effect of forest management intensity and tree neighborhood diversity on crown shape, ramification pattern and canopy space filling. The 3D puzzle of individual trees forming a stand will be assessed in detail and for both leaf-on and leaf-off conditions. We will focus on the processes that lead to deformation of trees (crowns and stems) as well as the resulting pattern of space occupation, especially in the canopy of the stands. Competition by neighboring trees and the effects of different trees species on the competition strength enforced on a tree individual can be quantified using the laser scanning data. Furthermore, we will be able to derive quantitative information on space occupation pattern using a novel approach that evaluates the 3D data on a high level of detail (cm) based on cubes that represent spatial units of varying size. We will also test whether or not niche-partitioning theory which predicts higher canopy space filling of species-rich temperate forests compared to species-poor stands can be confirmed.