Vegetational indicators as independent variables in forest growth prediction in West-Central Alberta, Canada

Vegetational variables were added to conventional edaphic and topographic properties as independent variables in tree growth prediction equations. Cover estimates of individual understory species, litter cover, deadfall cover, and advance regeneration density accounted for significant amounts of variability in lodgepole pinr ( Pinus contorta Dougl. var. latifolia Engelm.) and white spruce ( Picea glauca (Moench) Voss) mean annual increment in total volume (MAI) and site index (SI). R ² values for lodgepole pine MAI and SI increased from 0.24 to 0.66 and 0.49 to 0.71, respectively, and for white spruce MAI and SI increased from 0.53 to 0.86 and 0.58 to 0.91, respectively, with addition of vegetational variables. The inclusion of certain forest understory species as independent variables accounted for more MAI and SI variability than did some of the more frequently used soil and site properties. Inclusion of vegetational variables in a multiple regression may facilitate refinement of a productivity-oriented ecological classification of forest stands.