In the framework of the EFForTS Central Scientific Support Project I am involved in the analysis of trophic structure of the canopy food web using stable isotope composition (13C and 15N) of bulk tissues and compound-specific isotopes of amino acids in canopy arthropods. These analyses will reveal trophic positions and basal resources of the canopy arthropod food web and allow to compare them across different transformation systems. We will be able to trace changes in energy fluxes from basal resources to higher trophic levels as caused by land-use changes. (Further studies may include analyses on the regional scale within the anticipated EFForTS Landscape Assessment.)