Sustainability may be defined in terms of sustaining biophysical properties of the forest, in terms of sustaining a flow of goods and services from the forest, or a combination of the two. A combined definition follows: sustainable forests are able to provide goods and services to the present without impairing their capacity to be equally or more useful to future generations. The goods and services demanded of the forest include wood of specified quality; habitat for wildlife, fish, and invertebrates; recreational, aesthetic, and spiritual opportunities; sufficient water of appropriate quality; protection (e.g., against floods and erosion); preservation of natural ecosystems and their processes (i.e. allowing large forested landscapes to be affected only by natural dynamics); and the preservation of species.

To provide in perpetuity for future demands, the productivity, diversity, and function of the forest must be maintained and enhanced. A listing of key...