Precommercial thinning of naturally seeded slash pine increases volume and monetary returns

Abstract

A naturally seeded slash pine (Pinus elliottii Engelm. var. elliottii) stand, having up to 50,000 stems per acre, was precommercially thinned at age 3. Two thinning methods left single trees spaced 10 by 10 feet, and clumps of 6 to 8 trees spaced 10 by 10 feet, compared with the unthinned original stand. At age 23, the single-tree plots averaged 28 cords. Unthinned plots yielded less than 5 cords, which were mostly inaccessible because of numerous, submerchantable stems. Such gains in commercial volumes can justify a sizable investment in precommercial thinning. Thinning by age 5 to less than 1,500 trees per acre is recommended. Diameter and height growth were inversely related to stand density. Heights at age 23 increased about 4 feet for each 1,000-tree decrease in stocking. When evaluating or comparing slash pine site indexes over a very broad range of densities adjustments for trees per acre may be needed. Density effects are less important when the differences between stands are no more than 1,200 trees per acre, as would normally occur in managed stands.

Citation

Jones, Earle P., Jr. 1977. Precommercial thinning of naturally seeded slash pine increases volume and monetary returns. Res. Pap. SE-164. Asheville, NC: U.S. Department of Agriculture, Forest Service, Southeastern Forest Experiment Station. 14 p.