Acta Scientiarum Polonorum
Silvarum Colendarum Ratio et Industria Lignaria

Abstract The study presents radial and axial variation in the proportions of sapwood and heartwood in stems of common oak growing under varied growth conditions. Collected material was analyzed in order to find factors affecting irregularity in sapwood and heartwood zones in stems of trees representing investigated populations. The proportion of sapwood and heartwood in the stem and the rate of heartwood formation are influenced by crown size and transpiration efficiency of trees, social class of tree position as well as site conditions. The proportions of sapwood and heartwood vary also between age classes of trees. A considerable effect on the width of the sapwood zone in trees was found for crown size. In this case correlations were positive in both analyzed age classes, although in age class III they were weaker than in age class IV.