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The Whiskey Springs redwood commercial thinning study: a 29-year status report (1970 to 1999)
| Authors: | James Lindquist |
| Year: | 2007 |
| Type: | General Technical Report |
| Station: | Pacific Southwest Research Station |
| Source: | In: Standiford, Richard B.; Giusti, Gregory A.; Valachovic, Yana; Zielinski, William J.; Furniss, Michael J., technical editors. 2007. Proceedings of the redwood region forest science symposium: What does the future hold? Gen. Tech. Rep. PSW-GTR-194. Albany, CA: Pacific Southwest Research Station, Forest Service, U.S. Department of Agriculture; p. 305-316 |
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Abstract
The response of well-stocked second-growth coastal redwood stands to three levels of commercial thinning is reported after 29 years of growth. Commercial thinning treatments left 25 percent, 50 percent, 75 percent and 100 percent (uncut control) of the original basal area (400 ft2 per acre) in a 40-year old stand on the Jackson Demonstration State Forest. Stand values are given for basal area, number of trees, average diameter, and cubic foot volume and board foot volume per acre for the pre-treatment stand and five post-treatment inventory dates from 1970 to 1999. There were significant differences between the treatments in basal area, average diameter, and volume throughout the course of the study. Analysis of the periodic growth rate revealed strong statistical differences between the treatments in diameter growth but no significant differences in the basal area or volume growth (cubic and board foot). Total board foot volume was not statistically different between thinning treatments due to high variation but there is a trend indicating that the 25 percent retention treatment produced a lower yield than the other two treatments and the uncut control.Though this was not a regeneration harvest, regeneration was measured for inference to partial harvest management. The response of the understory regeneration was strongly affected by the density of the overstory canopy. A precommercial thinning study of the redwood sprouts showed a response only in the 25 percent overstory retention treatment.