1. Department of Biology; Lund University; Lund Sweden
2. Departamento de Sistemas y Recursos Naturales; Escuela Técnica Superior de Ingeniería de Montes; Forestal y del Medio Natural; Universidad Politécnica de Madrid; Madrid Spain
3. Southern Swedish Forest Research Centre; Swedish University of Agricultural Sciences; Alnarp Sweden
4. University of Eastern Finland; School of Forest Sciences; Joensuu Finland