Simulated Mapped Plots Derived from NL Spacing Trials for Sector Subsampling Study

The base data were collected from 3 early spacing trials located in western Newfoundland, Canada and established in the early 1980s. The dominant species was balsam fir with minor components of black spruce and white birch. Five spacing treatments were applied in this study areas using a randomized complete block design: control, or no spacing, (S00), 1.2m spacing (S12), 1.8m spacing (S18), 2.4m spacing (S24) and 3.0m spacing (S30). Each treatment was repeated 3 times per site (3×3×5 = 45 PSPs in this study). Treatments were applied to a 0.25 ha block (50m × 50m), and a circular permanent sample plot (PSP) was established near the center of each block. Plot sizes varied so that there were approximately 100 trees per plot following treatment. All trees 1.3 m and taller were identified by species and measured for diameter at breast height (DBH, nearest 0.01cm, BH = 1.3 m) and total height (HT, nearest 0.01 m). PSPs were remeasured at 3 to 5–year intervals but only the last measurements were used here. Stemwood, bark, branch, and foliage biomass (kg) was estimated for each tree using the Canadian national biomass equations. Total above-ground biomass (BM, kg) was estimated by summing these components.