1. Department of Geography Universitat de Barcelona Barcelona Spain
2. Botanical Institute of Spanish National Research Council CSIC Barcelona Spain
3. Department of Botany Kazimierz Wielki University Bydgoszcz Poland
4. Department of Biological, Geological and Environmental Sciences University of Catania Catania Italy
5. Faculty of Science Department of Botany Hacettepe University Ankara Turkey
6. Institute of Dendrology Polish Academy of Sciences Kórnik Poland