Partial cutting in old-growth boreal stands: An integrated experiment

The uncut boreal forest of eastern Quebec is largely composed of stands with an irregular structure. Traditionally, even-aged silvicultural systems have been used for these forests but a strong interest has developed in alternative approaches. In 2004, an integrated experiment was established to provide a general assessment of harvesting uneven-aged boreal forest stands with a wide variety of treatments. Here, we summarize the key results of this experiment, which involved four silvicultural treatments differing in the level of tree retention: a clearcut with advance growth protection, a severe partial cut protecting small vigorous merchantable stems (75%-90% basal area removed), and two patterns of selection cutting (35% basal area removed). We evaluated treatment effects on vegetation attributes and animal species assemblages. We also assessed whether or not selection cutting approaches could become broadly used on an operational basis by examining simple forms of application and assessing their economic profitability. We found that many attributes of old-growth forests can be maintained with selection cutting, even with simple approaches that do not invest in marking trees to cut. Unlike more severe cuts, silvicultural treatments with more than 55% tree retention largely maintain the animal assemblages associated with old forests. Financial analysis showed that selection cutting is profitable over the long time frame, but clearcutting remains more profitable. This greater profitability is related to the first entry, whereas future entries will be more profitable with selection cutting.