Hot Topics: Clearcutting and the Biology of Douglas-fir Forests Clearcutting and Wildlife Edge Effects

Most folks in Oregon have at least seen a clearcut, as clearcutting is both a highly visible and common reproduction method. It is also the most controversial.

A clearcut is an area of forest land where most standing live trees are logged in a single operation and few merchantable trees remain after the harvest. Some trees remain, as is required by the Oregon Forest Practice Rules, and prompt reforestation starts a new forest cycle. There are some similarities between a harvest clearcut and a forest opening caused by natural disturbances like wildfires,windstorms, flooding, or volcanic eruptions like that of Mount Saint Helens in southwest Washington State back in 1980. While clearcuts also differ from these disturbances, they do the job of creating the opening that many plants and animals need to flourish. There are benefits in using the clearcut method. For instance, a clearcut opens up the harvest unit, making it easier to control weeds and pests. It also makes the regeneration of sun-loving trees, like Douglas-fir, more successful. Since a clearcut receives more sunlight, there are improved growing conditions for other sun-loving shrubs, herbs, and grasses— food for edge specific animals like deer and elk.

Let's consider clearcuts from the perspective of wood fiber production. In a clearcut a larger volume of wood is harvested within a single harvest unit than if trees were selectively removed. One result of this is that we disturb a smaller amount of land to get the same volume, and it typically costs less. We can also use the clearcut method to remove large pockets of trees that are infected with an insect or disease, thereby limiting the infection if it is undesirable. Issues associated with clearcutting have led to controversy. First, a fresh clearcut is considered by many to be an eyesore— many people visit the forest to see large trees, and a clearcut has few large, standing trees. Some people look at a clearcut and do not see the healthy young trees regenerating on it. A clearcut to them appears barren even after young trees have begun to grow. Clearcuts also have been associated with landslides on steep high-risk sites. Finally, a clearcut changes the structure of an old forest for many years-- the general public prefers to see and visit older forests, and some plants and animals depend on older forests as habitat.

In Oregon we have rules that guide us on how we can and can't do clearcuts. Recent revisions to the Oregon Forest Practices Act now place a 120-acre maximum size limit on clearcuts and limit harvest activities adjacent to scenic highways. Some folks have begun to use smaller clearcuts of 30 to 40 acres in size, because smaller clearcuts increase road access for fire control, and are seen as less offensive than large ones.

Clearcutting and the Biology of Douglas-fir Forests |
Clearcutting and Wildlife | Oregon Forest Practices Act

Edge Effects