In essence, three systems of harvest cutting are applied on the National Forests: Selection cutting, seed tree cutting, and clear cutting, with variations based on specific terrain and other conditions.
Some forests are best managed through selection or partial cutting. In starting harvest of a virgin stand, older trees are cut first. So are the defective and diseased. Younger, healthier trees are encouraged, by this release from competition, to further growth—much like the weeding of a garden. The forest is also opened to stimulate new seedling growth. In seed tree cutting, the entire stand is logged except for a few carefully selected seed trees which are left to regenerate the forest. These, in turn, are harvested after the new stand has been successfully started.
Douglas-fir, however, is one of several species best managed with clear cutting in blocks. Selection cutting of the lusty giant has been tried in the National Forests, but with little success. It proved difficult to remove the tall Douglas-firs, standing over 200 feet, without seriously injuring others as they fell. Those remaining in a stand, shorn of protection from neighboring trees above and interweaving roots below, became victims of blowdown in high winds. Nor would Douglas-fir reproduce itself without benefit of full sunlight. Thus, clear cutting or patch cutting is practiced on blocks of 40 to 100 acres; this enables sunlight to reach the ground and to help the valuable Douglas-fir forest renew itself. Seeding by hand or by airplane and planting nursery-grown seedlings are methods used to reforest these large openings.
The Balances of Management
Throughout the 182 million acres of the National Forests other important factors are weighed in the balance with the need to produce timber. They may be the reason for heavy cutting, light cutting, or no cutting.