Increasing Aspen Production through Mechanical Strip-Thinning (December 1, 1993-May 31, 1994): Monitoring Report

Abstract

This project has five primary research tasks related to the determination of growth and yield of aspen in response to mechanical strip-thinning; analysis of disease incidence in thinned and unthinned stands and determination of the costs and economic feasibility of mechanical stripthinning of aspen. All activities for the 1993 growing season related to data collection are complete. The average diameter growth rate of the 200 largest trees in the network of new experiments is approximately 25 percent greater in thinned stands compared to unthinned stands on the same site. Laboratory analysis of soils were completed on all samples to complete that soils database for Task II studies. Measurement of tree growth and analysis of the older previously-thinned stands on the Chippewa National Forest are complete (Task III). Stand 3, which was thinned at age 11 and is now 25 years of age has 17. 9 merchantable cords standing volume per acre compared to an adjacent unthinned area which has 9.3 cords per acre. Stand 7, which was thinned at age 12 and is now 21 years old has 5.5 cords of merchantable volume per acre compared to 3. 3 in unthinned areas. An inventory of disease was done at Stand 3 and on one site on Blandin Paper Company land. Disease incidence on all plots will be measured this summer on the recently established studies. Economic analyses (Task V) were updated to reflect the rapid changes in aspen stumpage. Assuming a stumpage price of $22 per cord, the net present value (NPV) of thinned aspen is $429 per acre versus $168 for a no-thinning option; a difference of approximately $261 per acre.