Brad Withrow-Robinson, Forestry & Natural Resources Extension Agent, Benton, Linn and Polk Counties.


In my travels around the mid-Willamette Valley, I am seeing a lot of young conifer stands (generally Douglas-fir up to 20-something years old) with just too many trees. Why do I say there are too many trees?

I know many people in this part of western Oregon who are patiently waiting for their trees to grow, hoping to thin the trees in a selective harvest when the stand is about 25 years old. They plan to sell the harvested trees to cover costs and would like to break-even or make a bit back on establishment expenses.

All too often it is not working out that way. Instead, as the stand approaches the target age they find that trees have already become too crowded, with too many small, slow growing trees in the stand. The trees are still too small to support a profitable harvest thinning operation (also called a commercial thinning). To thin at that point is to do so at a cost, although it may be best for the woodland in the long-run. To delay the thinning and wait for the trees to grow enough to make the thinning harvest profitable is appealing, but deceptive. It may avoid the short term expense, but is likely to weaken the stand at a long-term cost of growth, stand stability and future options. It is a classic “pay now or pay later” situation.

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