For our clients who are growing planted stands of pine, thinning the stands is a very important tool for maximizing returns. Since it generates income for the client it cannot be viewed only as a means for Managing Forest Growth, and because its primary goal is to improve the stand, we don't list it under Timber Sales. Thinning is a management activity that deserves its own explanation.
Simply put, thinning a stand of trees means cutting down only some of the trees. In a pre-commercial thinning (see Managing Forest Growth) the trees are too small to have commercial value, and cut trees are usually left in the stand to decay. In a commercial thinning, the trees being cut are big enough to be sold, and are removed from the stand and sent to market.
One simple rule
The primary reason to thin pine plantations should be to remove the smallest and poorest-formed trees in the stand. This will ...
Concentrate growth on the most
valuable crop trees
An acre of land is capable of only producing so much wood. If the acre is fully stocked with trees, thinning the stand does not increase the amount of volume that that acre will produce. What thinning can do is increase the growth rate for individual trees by decreasing competition and increasing water, nutrients and sunlight available to each. Thinning then should be used to concentrate the growth of that acre of land on the biggest and best crop trees available by removing the poorest performers. Since these best sawtimber trees will be worth two to three times as much as the pulpwood trees they are replacing, it is obvious that a proper thinning can increase returns dramatically.
Reduce the risk from insects
The biggest risk to planted pine is from insects, most damaging being the Southern Pine Beetle. These insects are always present in the forest, and pine trees have natural ways to defend themselves. The insects only become a problem when trees become stressed (drought for example) and can no longer ward off attack. The first trees to succumb are the weakest, the smallest, the poorest formed, and the diseased. Only after the insects have built their populations in these breeding trees can they overwhelm the healthier trees in the stand. The obvious way to lower the risk? Remove the poorest and weakest trees in the stand when you thin.
Follow this one simple rule and the investment returns will be significantly greater at final harvest. Fail to execute it and a golden opportunity to manage the investment in your favor has been lost.