1. Department of Agriculture, Food, Environment and Forestry, University of Florence, Florence, Italy
2. Faculty of Engineering, Free University of Bozen-Bolzano, Bolzano, Italy
3. Alperia SpA, Department of Engineering & Consulting, Bolzano, Italy
4. Civil Engineering Department, Democritus University of Thrace, Xanthi, Greece
5. Forest Engineering Resources and Management Department, Oregon State University, Corvallis OR, USA