Nawrot, M., Pazdrowski, W. and Szymañski, M. 2008. Radial and Axial Variability of the Proportion of Sapwood and Heartwood in Stems of European Larch (Larix decidua Mill.). Baltic Forestry, 14 (1): 50-57

In this study an attempt was made to define a diversity in radial and axial share of sapwood and heartwood in stems of European larch (Larix decidua Mill.) grown under different forest site conditions.
The larch trees, which had grown in more fertile habitat as a fresh mixed forest site, was characterized by a bigger share of heartwood, and ipso facto a smaller share of sapwood than trees, which had grown in the conditions of coniferous fresh mixed forest site.
Trees from the age class IV (from 61 years old to 80 years old) distinguished themselves by lower share of sapwood than the larch trees which represented V age class (from 81 years old to 100 years old). This relationship was observed in both investigated forest site types. It was observed radial and axial irregularity of the share of both types of wood in stems the larch from investigated forest type sites and in age classes in connection with tree position in tree stand. On the share of sapwood and heartwood in tree stem and the velocity of heartwood making process probably can have influence the size and efficiency of transpiration, tree position in stand, as well as forest site conditions in which trees are grown.
Distinct influence of physiologically active tree crown on the sapwood zone in tree stems confirmed by calculation of the coefficient of correlation “r” characterized the relationship between the width of sapwood zone, and the volume and the area of tree crown projection.

Key words: European larch (Larix decidua), sapwood, heartwood, fresh coniferous mixed forest site (BMśw), fresh forest mixed site (LMśw)