Focus of Intensive Silvicultural Research on Coastal Douglas-Fir Over the Last 20 Years

Silvicultural regimes are becoming more intensive in the US Pacific Northwest, incorporating a multitude of treatments over the length of the rotation. Therefore, there is a need to understand not only how individual treatments affect forest productivity, but also how these treatments interact to determine productivity. To help launch the Planted Forest Productivity and Value Enhancement Program at Oregon State University, an extensive literature search was conducted over 9 different classes of silvicultural treatments and 10 different categories of measured responses. The objective was to examine the scope of our current knowledge base about intensive silvicultural practices in the Pacific Northwest, particularly the mechanisms by which various treatment combinations or regimes control the productivity of coastal Douglas-fir stands. The literature, 1984 through 2004, shows that studies were more likely to focus on a combination of silvicultural treatments or practices if they were applied during similar times of stand development. Very little documented research addressed the interactive effects of treatments applied sequentially over the rotation. Although most studies monitored growth, yield, and tree mortality, fewer studies investigated environmental, physiological, and morphological responses that are key to understanding and predicting how both tested and untested silvicultural regimes will affect forest productivity.