These landscape and stand level examples, illustrating the functions of some important forest composition and structures, indicate why practices such as clearcutting and elimination of old growth forests are not consistent with maintaining fully functioning forests. If the degradation caused by clearcutting and removal of old growth forests were more evident, people might be more willing to adopt ecologically responsible approaches to timber management.
However, because forests operate on such long timeframes, and because, for millennia, forests have been building biological legacies through many generations of trees that have lived and died, human activities that remove composition and structures do not immediately appear to be as damaging as they actually are. However, as timber managers continue to degrade composition and structures of forests, from landscape to stand levels, damage to forest functioning becomes cumulative. Eventually this approach leads to degraded ecosystems, which provide few ecological functions, compared to the fully functioning forests they replaced. Because forest degradation occurs relatively slowly, successive generations of human beings inherit degraded forests which they assume to be natural, “healthy” ecosystems. In other words, we don’t live long enough to see the results of our mistakes.
An ecosystem-based approach attempts to avoid loss of forest functioning by maintaining forest composition and structures from the smallest soil bacteria to the landscape patterns of a large forest watershed. We may not understand the functions of particular forest composition and structures; nevertheless, an ecologically responsible approach protects all composition and structures. When parts of the forest are altered during activities such as ecologically responsible timber management or tourism, provisions for the replacement of forest composition and structures are built into ecologically responsible plans and activities.
As well as providing for the protection and maintenance of forest functioning, an ecosystem-based approach fosters the development of diverse, sustainable human economies. Because an ecosystem-based approach creates the least modification to forest ecosystem composition and structures, it provides for the largest diversity of compatible forest uses. In other words, by maintaining trees on the sites where we practice timber management and by ensuring that ecologically viable old growth stands are found in each landscape, we provide an environment where the broadest spectrum of uses, from adventure tourism to timber extraction, can coexist. Such a range of activities is not possible where conventional timber management systems, such as clearcuts and tree plantations, are employed.
From a timber standpoint, because ecologically responsible timber management produces steady supplies of mature wood, the long-term economic benefits exceed those of conventional timber management practices. Mature wood—long-fibred and strong—is superior for many uses, from structural materials and pulp to furniture and fine cabinets. In comparison, short-fibred, juvenile wood is not as strong and will warp and twist easily. Mature wood is produced when the cambium layer (the single layer of cells between the wood and the bark) divides around dead branches or no branches. Obviously, increasing amounts of mature wood are produced as a tree gets larger and older.