1. Forest Research Institute , Department of Silviculture and Genetics of Forest Trees , Braci Leśnej 3, Sękocin Stary, 05-090 Raszyn , Poland
2. Warsaw University of Life Sciences , Institute of Forest Sciences , Department of Forest Management Planning, Dendrometry and Forest Economics, Laboratory of Dendrometry and Forest Productivity , Nowoursynowska 159, 02-776 Warsaw , Poland