The eastern boundary of Taxus baccata L. range transects Poland.
The analyses were performed on 34 yew populations which are protected as parts of nature reserves, as monuments of nature, or which are planned to be protected (Table 1). Samples were collected with the Pressler borer at breast-height from 25 trees in every area studied (in some cases, due to a low number of trees or constraints imposed by permits, the number of trees sampled was lower). The samples were collected from a total of 774 trees yielding 1307 profiles (Table 1).
The tree ring width was measured to 0.01 mm (a total of 99,628 tree rings were measured). The classical dating techniques (i.a., the cross-dating method) were subsequently used to reconstruct 34 local chronologies (Table 2). The longest dendrochronological series (267 years covering the period of 1741-2007) was that obtained from the yew trees growing in the “Cisy w Czarnem” reserve (CZA). Five chronologies were more than 200 years long; 12 were longer than 100 years, the remaining ones representing young trees: the shortest chronology, produced by the yews growing in the “Zdroje” reserve (ZDR) covered as short a period as 38 years (1965-2002) (Table 2). The mean tree ring width was 0.84 mm and ranged from 0.27 mm in the MI population to 1.47 mm in the ZDR yews.
Files with data of yew tree-ring width and yew local chronologies (for example: CJ chronology): 1st column - year, 2nd column and next - tree-ring width of individual trees in mm (tree1, tree2, …), next column - local chronology in mm (bold numbers), last column - number of samples in a given year.
(2023)