Monday, January 12, 2009

Thinning

Trees have a reputation for slow growth, and that is not always deserved. Overstocked stands of trees do grow slowly, but with proper thinning, they will turn on and produce wood in a hurry. This bottomland site will easily grow trees with rings 1/2 inch or wider, but the tight spacing has them producing mostly height and not diameter. A quick count on the stump below shows that the trees are about twenty-five years old, and that they are slowing down from overcrowding. The largest trees are about eight inches in diameter, so they have averaged about six growth rings per inch.

The basic method in an overstocked stand like this one is to select a tree with good potential for a crop tree, and release it from competition by cutting the trees around it on three or four sides. The extra space allows the crown and roots to expand, and the tree will increase in diameter quickly. Landowners can expect forty to fifty good trees per acre to make it to rotation on land like this, so helping a crop tree approximately every thirty-three feet is common advice for large sapling and small pole stands. (Thirty-three X Thirty-three =Forty per Acre)
Thinning early in the life of a stand allows a landowner to select the more valuable species and the best quality stems to dominate, and to dramatically decrease the number of years needed to produce a crop of timber.

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