SELF-THINNING MODELS FOR EVEN-AGED STANDS OF PINUS-SYLVESTRIS, PICEA-ABIES AND BETULA-PENDULA

Self-thinning models were developed to describe the relationship betwe en the stem number and mean diameter of even-aged and monospecific tre e stands undergoing self-thinning. The models were developed separatel y for Pinus sylvestris L., Picea abies (L.) Karst. and Betula pendula Roth. stands. Data from 41 unthinned permanent sample plots were used. According to Reineke's equation and the -3/2 power rule of self-thinn ing, a log-log plot of average tree size and stem density will give a straight, self-thinning line of constant slope. According to this stud y, the slope of the line consistent with Reineke's equation varies for different tree species. Within tree species, the intercept of the sel f-thinning line varies according to site index.