Fifteen-year results of black spruce uneven-aged silviculture in Ontario, Canada

An uneven-aged silviculture experiment was established in second-growth peatland black spruce (Picea mariana [Mill.] B.S.P.) stands in the boreal forest of northeastern Ontario, Canada in 1994. Three harvest treatments along with an unharvested control were applied in three replications. Fifteen-year results indicate that light- and medium-intensity harvest treatments maintain stand structure suitable for the continued application of uneven-aged silviculture treatments. Based on basal area growth trends and the development of stand structure, a cutting cycle of 2025 years appears to be feasible for these treatments. Future harvests will likely yield a higher proportion of larger diameter trees with a greater value. The heavy harvest intensity treatment will result in a greater fluctuation of the growing stock and a longer cutting cycle. Without cutting treatments, the control treatment may eventually develop a stand structure that is unsuitable for the implementation of uneven-aged silviculture.