Abstract
The market for southern pine first thinnings is soft. Thus, forest managers are planting at wider spacings, and using weed control and fertilization to grow chipping-saw and sawtimber trees in shorter rotations. A 21-year-old unthinned spacing study was sampled to determine the effect of initial spacing on wood quality and yield per acre of planted loblolly pine (
Pinus taeda L.). The study area was planted in the Coastal Plain of GA in 1984 with loblolly pine family 7-56 seedlings. Twenty-one trees from each of seven spacings ranging from 6 by 8 feet (908 trees per acre) to 12 by 12 feet (302 trees per acre) were sampled. Total stem green weight per acre of wood and bark to a 3-inch d.o.b top was estimated to be highest in the 6 by 12, 8 by 10 and 8 by 12 foot spacings. Estimated volume of lumber per acre was slightly higher in the 8 by 12 spacing compared to the 12 by 12-feet spacing. Breakeven stumpage price per acre was highest for the trees planted at 8 by 12-feet spacing. Average number of knots, knot diameter, and average maximum knot diameter increased with increased spacing.
Parent Publication
Citation
Clark III, Alexander; Daniels, Richard F.; Jordan, Lewis; Schimleck, Laurie. 2010. Impact of initial spacing on yield per acre and wood quality of unthinned loblolly pine at age 21. In: Stanturf, John A., ed. 2010. Proceedings of the 14th biennial southern silvicultural research conference. Gen. Tech. Rep. SRS–121. Asheville, NC: U.S. Department of Agriculture, Forest Service, Southern Research Station. 333-337.