Rotation-Age Results from a Loblolly Pine Spacing Trial

This study reports cubic-foot volume yields for particular product definitions from a 25-year-old loblolly pine spacing trial and shows how closely, in the absence of thinning, total and merchantable wood production are linked to initial spacing. Results at the close of the study indicate that (1) high-density plantations can be managed on short rotations for woody biomass production; (2) pulpwood yields can be maximized at a planting density in the neighborhood of 680 trees/ac; (3) the production of solidwood products, without imposing thinning, requires lower establishment densities, with as few as 300 trees/ac planted resulting in a substantial proportion of the total yield recovered as large sawtimber; and (4) a ratio of between-row to within-row planting distances of at least 3:1 does not substantially affect yield production. Considered together, the results of this study suggest that no single planting density is optimal for the wide array of product objectives for which loblolly pine is managed in the South. Rather, managers must select an appropriate planting density in view of the products anticipated at harvest.