Ministry of Forests

Cariboo Region Research Section


Establishing Douglas-fir Plantations in the Dry Belt of Interior British Columbia

ABSTRACT

Douglas-fir plantation failure has been extensive in the dry belt of Interior British Columbia. High seedling mortality may be attributed to: frost, mid-season drought, stock quality problems, cattle damage, and vegetation competition from native and domestic grasses.

Preliminary results are presented from field trials in the Cariboo and Kamloops Forest Regions. These trials were designed to test various treatments to improve seedling survival and growth such as: site preparation, fencing to exclude cattle, and pine nursecropping. Seedling survival, condition, height and diameter growth, and damage codes were assessed for a maximum of six growing seasons.

On the driest sites, Interior Douglas-fir zone (IDF), seedling survival and annual height growth improved when planted in a trench or a v-plow path. However, annual height growth was below 3 cm on all treatments. Cattle severely damaged seedlings planted in some of the untreated areas and on paths created by v-plows. Pine nurse-crops helped alleviate damage from frost and cattle.

On moister sites, Subboreal Spruce zone (SBS), seedling survival was better than in the IDF. Survival improved with any form of mechanical site preparation. Also in the SBS, container seedling performance was better than bareroot performance. Cattle damage was more prevalent on areas prepared by v-plows.

Keywords: Pseudotsuga menziesii, site preparation, cattle grazing, nurse crops

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