Focus on Old Growth Misses the Mark

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The Sensible Environmentalist

Dear Dr. Moore: How do I know if my deck comes from an old growth forest?

Wood products are not tracked in terms of each tree’s age, so the short answer is that you don’t.

But there are other ways to ensure the protection of old growth forests. The important thing is to set aside enough wilderness areas that there is ample old growth — and every other age — across the forest landscape.

This is something that North Americans have taken to heart. The amount of parks and other protected land in the United States and Canada has greatly increased in recent years, and it comes closer to achieving the United Nations target of 12% of the land base than that of any other region in the world.

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The debate over old growth has been presented as good versus evil: beautiful old forests or barren clear-cuts. But forests are in a constant state of change. North American forests face large natural disturbances such as fire or disease on a regular basis — which is simply to say that a forest set aside as old growth usually won’t be old growth forever. The process is cyclical, not a one-way street that leads either to the perfect forest or permanent forest loss.

Old growth is a complex subject, partly because there is no universal definition:

• Age—As a popular term, “old growth” describes forests containing trees that are big and old, usually older than 200 years. Scientifically, it means forests that have reached the age of maturity; for alder or birch this would be 50 years, while for redwood or Douglas-fir it would be 500.

• Characteristics—Many people consider this more important than age. Old growth characteristics include standing dead trees large enough for cavity nesting birds, fallen dead trees as habitat for insects, fungi and small animals, and a fully developed diversity of plants, shrubs and trees. In some types of forest (such as coastal Douglas-fir), these features may appear after just 70 years.

Old growth forests provide important habitat, are beautiful and (in areas where fires are infrequent) often live to be centuries old. However, it is equally true that young forests provide important habitat, are beautiful and contribute to our material needs. The fact is that different species of wildlife have evolved to take advantage of all ages of forest, from recently disturbed, through young, middle-aged and old growth.

I believe that a sensible environmentalist would support a balance of all these types across the forest landscape.

(Questions may be sent to Dr. Moore at the following e-mail address: