1. Department of Geography; Johannes Gutenberg-University; Johann-Joachim-Becher-Weg 21 55128 Mainz Germany
2. US Forest Service Northern Research Station; 180 Canfield St. Morgantown WV 26505 U.S.A.
3. Faculty of Forestry; University of Applied Sciences Weihenstephan-Triesdorf; Hans-Carl-von-Carlowitz-Platz 3 85354 Freising Germany
4. Department of Geography; University of Cambridge; Downing Place CB2 3EN Cambridge U.K.
5. Swiss Federal Research Institute WSL; Zürcherstrasse 111 8903 Birmensdorf Switzerland
6. CzechGlobe Research Institute CAS and Masaryk University; Kotlářská 2 61137 Brno Czech Republik