To determine the effects of different levels of post-thinning density on the growth and development of mid-rotation lodgepole pine.
The study tests five levels of thinning (20, 40, 60, 80, and 100% of "normal" stocking) plus an unthinned control. Actual post-thinning densities range from ~ 750 st/ha (20% of normal stocking) to 2900 st/ha (100% of normal stocking). The mean density of the unthinned (control) treatment was ~ 4900 st/ha at the time of trial establishment. Each of the six treatments is replicated twice, for a total of 12 treatment plots. Treatment plots vary in size depending on thinning level, and range from 0.36ha to 0.82ha.
The study was established in 1952 in a 53-year-old lodgepole pine stand northeast of Canal Flats within the dry cool subzone of the Montane Spruce biogeoclimatic zone. The installation was re-measured on about a 5-year cycle until 1998, when it was switched to a 10-year re-measurement interval.