With pre-commercial thinning, Millwood removes trees prior to them reaching merchantable size. Pre-commercial thinning releases trees in overstocked stands, reducing densities to prevent stagnation and increasing the growth of remaining trees. Millwood removes scattered trees throughout the timber stand, creating larger openings in the forest canopy that will close as the surrounding trees grow. This thinning frequently does not establish regeneration (a new generation of young trees in the understory), although in certain cases it can.
Pre-commercial thinning, also known as Timber Stand Improvement, enhances the quality of growing timber, rather than harvesting and selling the timber.
- Landowner objectives determine which trees Millwood removes during pre-commercial thinning.
- To enhance future timber production, Millwood removes undesirable species, poor-formed trees and slow-growing individuals.
- Depending on wildlife considerations, Millwood sometimes leaves poor-formed or cull trees to provide wildlife habitat.
- A common mistake in pre-commercial thinning is to leave too many trees in the residual stand.
- Generally, pre-commercial thinning removes 40 to 60 percent of the trees in a stand.
Several thinning operations may take place before the stand reaches maturity.
In a commercial thinning operation, Millwood performs an intermediate harvest where merchantable wood removed covers part or all of the cost of harvesting. In a commercial thinning operation, all or part of the felled trees are extracted for useful product. Commercial thinning, when carried out on the right stands at the right time and under appropriate stand conditions, is a valuable strategic management tool for the landowner.