Tree mortality is a natural, ongoing process in the forest. Young forests with small trees support many thousands of individual trees per acre. As the forest matures and individual trees become larger, many trees are crowded (by faster growing neighbors) and die.

Thinning is a forestry technique used to "capture" some of the potential mortality by harvesting selected trees. Thinning reduces crowding and, by redistributing the growth potential to the most desirable trees on the site, the overall health, vigor, and growth of the remaining stand is increased. Those "residuals" or remaining trees may have been selected for one of many reasons, including wildlife habitat (a "cavity" tree), timber, or aesthetics. Thinning also provides some intermediate return on a landowner's long-term forest investment.

Three of four of the treatments demonstrated are thinnings. The plots were fully stocked before harvesting, there were no openings in the canopy. Viewed from above, the crowns or branches of the trees seems to touch one another in a continuous, green carpet. There was no room for individual crowns to grow and expand. The purpose of our thinning treatments was to reduce the stocking or density to about 60 percent to give the residual trees additional room to reach out, thus increasing their rate of growth.

An improvement thinning represents the professional foresters-recommended silvicultural treatment for this forest stand. It was designed to meet a set of specified objectives, including production of timber for income, maintenance of wildlife habitat, and protection of the soils and related resources. In an improvement thinning, the resource professional balances the landowner's management objects with forest conditions on the site and markets, and selects individual trees to cut or to leave on the basis of species, spacing and tree quality.

This particular treatment improved the stand for timber while maintaining species diversity and retained den trees and valuable food producers for wildlife.

Key Points

• Flexible management objectives
• Can improve for timber, wildlife, aesthetics, etc.
• Provides some immediate income