P2G: Causes and effects of leaf trait variation (TreeDì_P2G Leaf trait variation )

Chemical and morphological leaf and root traits of trees have been shown to vary (1) among species, (2) within species and among individuals, and (3) within individuals. So far it is unknown how these three components of trait variation contribute to complementarity effects of ecosystem functions. In the TreeDì design with comparing mono- and heterospecific TSPs, complementarity effects are easily visible in over-yielding. Increased complementarity can be achieved through increasing trait variance between the two trees of a TSP or by increasing trait variance within the individual TSP trees. In addition, the contribution of the three components of trait variation to complementarity can vary with the abiotic environment, such as differences in soil nutrient supply, and the biotic environment, such as differences in tree species identity and diversity of the local neighborhood. Objectives: to quantify to which degree leaf traits are adjusted to different light conditions along the interaction plane of two tree species to analyze trait variation as a response to species and functional diversity of the local neighborhood of the TSP andthe dependence of traits and trait variation on soil nutrient availability to relate trait variation and performance of the TSP to quantify different components of trait variation to complementarity effects of ecosystem functions