A2 TRENCH (Tree-Ring Environmental Network for Climate Change Monitoring): Developing a tree-based indicator system for environmental change impacts on forest ecosystems in southern Ecuador.

PI(s) for this project:

Prof. Dr. Achim Bräuning


 The suggested project aims at the development of a tree-ring based indicator system on climate and environmental change impacts on forest ecosystems in Southern Ecuador. We follow a multiparameter approach that shallintegrate various information sources in wood into one indicator system by modelling approaches. We will measure quantitative variations of wood anatomical parameters in relation to climate soil and soil factors. Long- erm growth rates of trees and diurnal amplitudes of stem diameter variations shall be measured with high-resolution electronic dendrometers. In addition, interannual variations and long-term trends of various stable isotope  species over the past 30 years shall be analyzed. By combining of growth data and stable carbon and oxygen isotope analyses it is possible to distinguish if changes in intrinsic water use efficiency are caused by changes of assimilation or stomatal conductance. Analyses of stable nitrogen isotopes in wood allow conclusions about changes of soil nutrient cycling that is expected with worldwide increasing rates of nitrogen input in tropical forest ecosystems. The project will work anelevation gradient, including tropical dry forests, perhumid mountain rainforests and very wet treeline ecotones towards the paramo. The nutrient manipulation experiment NUMEX simulates  the impact of increasing atmospheric nutrient input so that reactions of intrinsic water use efficiency and other growth parameters of specific tree species of all forest ecosystems can be studied. To detect nutrient-triggered species-specific changes in the reaction pattern on short-term drought events, intra-annual variations of stable carbon and oxygen isotopes shall be carried out for the past six years.