Forest ecosystems are characterized by a complex of various elementary factors: plant, animal and micro-organism communities, abiotic factors (climate, abiotic soil substance) and humanity as an integral component of ecosystems. Beside evolutionary processes it has been human use and management which has considerably influenced landscapes and (forest) ecosystems. Due to increasing human use there has been an ongoing trend to a shift from natural landscapes to land developed and cultivated by man. In most European countries there has been intense human pressure on forests and correspondingly an alteration of forest structure and composition. Losses of forested area to settlement and urbanization and transport infrastructure are compensated by afforestation of agricultural and other land, which leads to slow expansion of forests. Consequently, in most European forest ecosystems changes of nutrient, water and energy cycles, genetic diversity, species composition, habitats and landscape structures can be observed. For the implementation of the ecosystem approach defined under the Convention on Biological Diversity (1999-2003) a lot research activities have been done on the anthropogenic impacts on forest biodiversity with regard to legal requirements for action, research and information needs, monitoring systems and instruments for decision-making. The Institute of Silviculture has a long scientific record on the analysis of natural reserves, gene conservation forests and protected areas. Starting from 1963 basic research was done by the activities led by Prof. Dr. Zukrigl and Dr. Kral. Results of a recent study on the ecosystem approach of the CBD can be found here: http://www.biodiv.org/doc/case-studies/esys/cs-esys-at-fea-en.pdf).