The inclusion of forests as potential biological sinks in the Kyoto Protocol to the United Nations Framework Convention on Climate Change (UNFCCC) in 1997 has attracted international attention and again has put scientific and political focus on the world's forests, regarding their state and development. The international discus- sion induced by the Kyoto Protocol has clearly shown that not only the tropical rain forests are endangered by man's activities, but also that the forest ecosystems of boreal, temperate, mediterranean and subtropical regions have been drastically modified....