Croissance en hauteur de l'épinette noire: région de Lebel-sur-Quévillon et de Dolbeau au Québec

Height growth of black spruce was studied from stem analysis in 72 circular plots of 0.1 ha located in the Lebel-sur-Quévillon and Dolbeau regions, province of Quebec. Tree age analysis showed that only 52 of these plots were evenly aged; therefore, only these were retained in the present study. Mean age determined at diameter at breast height was as variable as mean total age. The comparison of Plonski's and Vézina and Linteau's parameterized site-index curves suggested that Plonski's model is more suitable for asymptotic growth of black spruce. The comparison of parameterized average height curves from 52 plots with Plonski's curves indicated that black spruce height growth in these regions is not uniform; four different growing forms corresponding to temporal structures can be distinguished. These growing forms can have asymptotic or linear curves; these can coincide with or cut across the Plonski's site-class curves, according to the increase or decrease in height growth with age. Finally, the growing forms are also found by parameters of Korf's growth function, by height increments, and by ages at which height increment is highest.