Gabriel Danyagri, Research Silviculturist, Ministry Of Forests

Abstract of Presentation

Companion planting Research Trial

In British Columbia, Douglas-fir forests are highly valued resources for timber, wildlife, esthetics, range and recreation. For instance, functional mule deer winter range (MDWR) is characterized by multi-aged stands dominated by mature Douglas-fir trees that intercept snow, provide thermal cover, and winter forage. In recent years, however, stand-replacing wildfires have destroyed large areas of MDWR, especially in the Cariboo Region. Following these wildfires, salvage logging operations was undertaken to recover valuable timber. This required that salvage logged areas be reforested to a Douglas-fir leading stand at free growing/maturity to support ecosystem values, including mule deer winter habitat. However, Douglas-fir regeneration failure in large openings is common across the Interior Douglas-fir (IDF) biogeoclimatic zone in the Cariboo Region. Environmental stressors such as summer frost and drought stress, are major limiting factors to the successful regeneration of Douglas-fir. Therefore, Douglas-fir regeneration often require protection under mature standing trees or snags.

In dry sites, Douglas-fir natural regeneration often occurs under pioneer tree species such as trembling aspen and lodgepole pine. These pioneer species serve as nurse-trees to the regenerating Douglas-fir. However, following salvage logging operations, successful regeneration of Douglas-fir under mature pine or aspen may not be possible. Therefore, planting Douglas-fir alongside these pioneer species may improve regeneration success by reducing the severity of environmental stresses associated with large openings.

The primary objective of this study is to determine if companion planting of Douglas-fir with lodgepole or trembling aspen would improve its survival compared with Douglas-fir alone