Effect of vegetative competition on regeneration of white spruce

Abstract

The rate of invasion and height growth of vegetation in logged-over areas were studied on four forest site types in the white spruce – alpine fir (Piceaglauca (Moench) Voss – Abieslasiocarpa (Hook.) Nutt.) forests north of Prince George, B.C. On Cornus–Moss, Aralia–Dryopteris, and Devil's Club site types, which generally had full stocking, vegetation that grew under the canopy of trees was replaced after logging by aggressive pioneer species. Annuals were the first to invade the logged-over area, followed by biennials and perennials. The invasion of shrubs was the slowest. After logging, 6 or 7 years elapsed before vegetation became a serious hindrance to regeneration and, by that time, white spruce seedlings planted immediately after logging were tall enough to withstand competition. On the Alluvium site type, where stocking is usually open and shrubs and grasses that thrive in the logged-over areas are present, spruce seedlings were overtopped during the first growing season and eliminated as the density of shrubs increased.