|MadSci Network: Environment & Ecology|
Trees are a renewable resources, but forests are not, and it it vitally important that you understand the difference. Trees can be grown and harvested like any other crop, and in this sense trees are a renewable resource. But a forest is more than trees, it is a complex community of diverse and interacting organisms. When you consider cutting down trees in a forest, either clear or selective cutting, then the whole forest, as an intact community, is the resource being consumed, and it is not renewable. Certainly some number of trees can be cut and removed from a forest without destroying the forest; tree death and growth are a part of forest dynamics. We even know that the canopy gaps produced by tree death are responsible for maintaining species diversity. Theoretically trees could be harvested at a rate similar to that of natural tree cycling without damaging the forest, but this number is so low that it falls below a commercial feasibility except for very low impact, labor intensive methods. Planatations of trees could meet all our forest product needs, so what is the problem? Trees take a long time to grow to a harvestable size and for a long time logging companies did not see that it was in their own best interests to replant trees. Forests were plentiful and they didn't have to pay much for the logging rights. Now forests have dwindled, although nice strips of trees are left along highways to preserve the image of plenty, and there are not enough plantations with enough trees that are old enough (big enough) to meet our needs. This results in logging companies putting pressure is being put upon the federal government to open more public lands for logging. In Homer Alaska I watched as truck load after truck load of logs were loaded on ships bound for Japan, another wood/paper hungry nation. So even now forest destruction in the USA exceeds our own needs. Those Alaskan forests are being cut simply to make somebody wealthy. Some people may think forests are an endless resource, but they are either very ignorant or economists (or both). There is no question that loss of forest cover has affected climatic patterns and resulted in significant soil and stream degradation, not to mention the loss of habitat. Most people are unaware how human demands for wood and paper have made deforestation a world-wide ecological problem. I have traveled widely, one of the best things about being a professional botanist, and I have seen the effects of deforestation almost everywhere. It's shocking to know what has been lost. It is often said that those who do not learn from history are doomed to repeat the mistakes of the past. The collapse of any number of ancient civilizations appears to be either in part or wholly the result of deforestation. Did you ever wonder about why the ancient civilizations in Greece or the Middle East lived in such arid and rather desolate looking surroundings? These civilizations were based upon wood for construction and energy, and the great forests of these areas are gone. What you see, our modern image, is what is left behind when all the forests have been cut. The eastern United States was once heavily forested, and deforestation in the tropics continues at an alarming pace. A representative of a paper company speaking to a group of forest biologists told us, "We plant 10 trees for every tree we cut down." And then someone asked him what species were being harvested and what species were being planted? "What difference does that make?" he asked. "It's the difference between a forest and a corn field", we said. So when someone says "Trees are a renewable resource", be ready to ask them, "But what about forests, are they a renewable resource too?"
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