Effects of root rot on the growth of balsam fir

Abstract

Growth increments were compared on balsam fir (Abiesbalsamea (L.) Mill.) trees with varying amounts of decay on the stump (15 cm above ground) that originated from the roots. In 1612 trees, from 20 to 156 years of age on 139 plots across northern Ontario, the average height and radial increments over the last 3 years were 13.5 and 10.9% smaller, respectively, in trees with ground-level decay compared with trees having no decay at this level. Stand basal area was more useful than tree age as a stratification variable for revealing the effect of root rot on growth. Growth reductions were the smallest in trees with intermediate surrounding basal areas and in trees on drier or heavier textured soils.