“Silviculture” is the science and practice of perpetuating forests by growing trees on a large scale (that is, not a single tree, but rather growing whole “stands” of trees). Different methods of growing timber stands can be divided into “selection” and “even aged” methods. In selection harvesting, individual trees or small groups (up to 2 ½ acres) of trees are cut. New trees are established by natural seeding into the openings created by this cutting, maintaining a forest that is a mix of trees of different age and size classes. In even aged harvesting, trees are removed in larger areas (typically 15 to 20 acres) so that a new stand of trees that are all about the same age is created. Foresters often plant trees to create these new stands, although seeding by trees left for that purpose is possible.
Other cutting methods, such as commercial thinning of trees to improve spacing and maintain growth, and “sanitation-salvage” harvesting of dead, dying, and diseased trees, are considered “intermediate” or maintenance harvests, not designed to establish a new timber stand.
The following table provides a brief description of the attributes of different silvicultural methods:
|Attribute||Single Tree Selection||Group Selection||Seed Tree||Shelterwood||Clearcut|
|Ease of establishment of new trees||Difficult||Difficult||Varied w/ natural regen; good if planted||Varied w/ natural regen; good if planted||Good|
|Site Prep Needed?||None||None||Usually||Usually||Usually|
|Short term disturbance||Low||Moderate||Mod to high||Mod to high||High|
|Utilized in CA?||Often||Seldom||Seldom||Seldom||Often|
|Control of growth factors (spacing)||None||Little||Good if planted||Good if planted||Good|
A downloadable PDF of the Intro to Silviculture page is available by clicking here