Permanent sample plots were established at Watson Lake in 1961 and remeasured in 1978, 1982 and 1987. The plots were located in three types of stands: Stratum RC -- an area cleared of vegetation about 1941 which subsequently regenerated to lodgepole pine (Pinus contorta Dougl.); Stratum RS -- an area largely cleared (also about 1941) but containing some residual pine, black spruce (Picea mariana (Mill) BSP), and white spruce (Picea glauca (Moench)Voss); and Stratum MA -- a mature, undisturbed lodgepole pine- spruce stand. All three strata contained a minor component of hardwoods, mostly trembling aspen (Populus tremuloides Michx.). After conversion to metric units in 1978, the plots were 400 m2 in size. Data from 19 plots in each of strata RC and RS and from 10 plots in stratum MA were available for analysis. Stratum RC grew from 4 to 72 m3 ha-1 (gross total volume) between 1961 and 1987. Pine comprised the largest component in this stratum (about 80%) throughout the period. Growth rate for the three intervals between measurements was constant at 2.5 m3 ha-1 yr-1. Stratum RS grew from 1 to 49 m3 ha-1 between 1961 and 1987. Pine also comprised the largest component in this stratum but only at 58%; it remained constant at that level throughout the period. The growth rate in stratum RS increased from 1.3 to 2.7 m3 ha-1 yr-1. Stratum MA grew from 174 to 224 m3 ha-1 between 1961 and 1987. Pine again comprised the largest component in this stratum, decreasing slightly from 57 to 51% during the period. Overall growth rate in stratum MA also decreased, from 2.1 to 1.0 m3 ha-1 yr-1. The decrease occurred in pine and white spruce, while black spruce increased in growth.
