Thinning Red Pine Plantations and the Langsaeter Hypothesis: A Northern Minnesota Case Study
Abstract:The Langsaeter hypothesis states, “The total production of cubic volume by a stand of given age and composition on a given site is, for all practical purposes, constant and optimum for a wide range of density of stocking. It can be decreased, but not increased, by altering the amount of growing stock to levels outside this range.” We used a multistep approach to test this hypothesis in a 46-year-old red pine plantation growing on a site of moderate quality in northern Minnesota. First, we used stem analysis data to construct tree-level red pine volume equations and compared them to existing equations. We then calculated stand-level volume. Doing this allowed us to evaluate the performance of two stand-level volume prediction equations, a growth and yield spreadsheet package, and a computer simulation model using 10-year pre- and post-thinning measurements. Tree volume prediction equations were similar to existing equations. For 10-year projections, the stand-level volume prediction equations and growth projection models provided volume estimates within 10% of actual volumes on average. Ten-year post-thinning measurements showed that a geometric, strip thinning to 100 ft2 of basal area resulted in a 40% volume gain, a crown thinning to 125 ft2 of basal area a 35% volume gain, and a low thinning to 140 ft2 of basal area a 30% volume gain, while an unharvested control had a 22% gain in volume relative to residual stand volumes. Although we found the 10-year volume growth varied less than 1 cord ac−1 between residual growing stock volumes retained in this study, we do not have strong evidence to support the Langsaeter hypothesis for red pine.
Document Type: Regular Article
Affiliations: Department of Forest Resources, North Central Research and Outreach Center University of Minnesota 1861 Highway 169 East Grand Rapids MN 55744-3396
Publication date: March 1, 2005
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- Each regional journal of applied forestry focuses on research, practice, and techniques targeted to foresters and allied professionals in specific regions of the United States and Canada. The Northern Journal of Applied Forestry covers northeastern, midwestern, and boreal forests in the United States and Canada.
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