Growth of Lodgepole Pine After Mechanical Strip Thinning in Alberta: 15-year Results

An operational thinning in a 25-year-old lodgepole pine (Pinus contorta Dougl. var. latifolia Engelm.) stand in Alberta resulted in nearly a 50% increase in diameter at breast height (dbh) and height increment in the last 5 years. Initial stand density had no effect on dbh increment beyond that of initial tree size. The release effect extended throughout the narrow (around 1.5 m) leave strips. Mortality continued to occur at about the same rate in both treated and untreated plots, thus reducing the need for follow-up selective thinning. Although the treated area had much lower stand volumes, it has a faster growth rate and may catch up or even surpass the untreated area in merchantable yield at harvest.