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Individual Highlight

Sustaining Tree Quality Under Three Harvesting Methods

Photo of Proportion of grade one trees harvested over time for three harvest types. John Brown, USDA Forest Service.Proportion of grade one trees harvested over time for three harvest types. John Brown, USDA Forest Service.Snapshot : The quality of trees grown and harvested under various methods exhibits changing patterns over time. A Forest Service scientist studied three methods to determine the sustainability of the options over the long term. Although the number of trees harvested was initially significantly higher from both patch cutting and single tree selection, the percentage of trees cut from diameter-limit plots decreased over time whereas the patch cutting and single tree selection practices have increasing percentages. At close to fifty years, the practices have converged in percentages and suggest that the diameter practice is on an unsustainable curve while patch cutting and single tree selection are more sustainable choices.

Principal Investigators(s) :
Brown, John 
Research Location : West Virginia; Pennsylvania; Ohio; Kentucky
Research Station : Northern Research Station (NRS)
Year : 2014
Highlight ID : 641

Summary

In the practice of silviculture, foresters manage forest characteristics for a variety of resource objectives. While timber is often of interest, other objectives include wildlife, clean water, or recreation. For all of these, sustainability can be interwoven as an additional objective. Long-term studies on the Fernow Experimental Forest in West Virginia have addressed several of these objectives. Forest Service scientists examined harvest records from nearly 50 years on three types of cutting practices, diameter-limit cutting, patch cutting, and single-tree selection, to compare tree quality. They found that the percentage of cut grade one trees at harvest is significantly different among the three cutting practices at the 15- and 30-year marks in the study, with the diameter limit percentages exceeding those in both the patch cutting and single tree selection practices. However at year 45, analysis showed that the diameter limit harvest percentages were not different than the patch cutting, nor the patch cutting from the single tree selection. More importantly, the long-term trajectory of the percentage of cut grade one trees from the diameter limit cuts was decreasing, while the trajectory of this percentage for the patch cutting and single tree selection practices was increasing. This is evidence that diameter limit cutting is not sustainable over the long term.