Crown Development in Conifer Stands in Scotland as influenced by Initial Spacing and Subsequent Thinning Treatment

This paper deals with the different influences affecting the development of the crown per cent. in Norway spruce ( Picea abies ), Sitka spruce ( P. sitchensis ), and Douglas fir ( Pseudotsuga taxifolia ) stands and gives for these three species development curves of crown per cent. according to top height, thinning grade, and quality class. It shows the effect of different thinning grades on the crown surface (and crown volume) of the mean tree and the whole stand, together with the relationship between volume increment and crown surface (and volume). The contribution of the different canopy classes to the total increment of the stand is assessed. Finally the relevance which these findings might have on thinning techniques is considered.