The Rate of Deforestation
The actual rate of deforestation is difficult to determine. Scientists study the deforestation of tropical forests by analyzing satellite imagery of forested areas that have been cleared. Figure 2 is a satellite image illustrating how scientists classify the landscape. Contained within the image are patches of deforestation in a distinctive "fishbone" of deforestation along roads. Forest fragments are isolated areas left by deforestation, where the plants and animals are cut off from the larger forest area. Regrowth-also called secondary forest-is abandoned farmland or timber cuts that are growing back to become forest. The majority of the picture is undisturbed, or "primary," forest, with a network of rivers draining it.

Figure 2. Satellite image of deforestation in the Amazon region, taken from the Brazilian state of Para on July 15, 1986. The dark areas are forest, the white is deforested areas, and the gray is re-growth. The pattern of deforestation spreading along roads is obvious in the lower half of the image. Scattered larger clearings can be seen near the center of the image.

The Food and Agriculture Organization (FAO) estimates that 53,000 square miles of tropical forests (rain forest and other) were destroyed each year during the 1980s. Of this, they estimate that 21,000 square miles were deforested annually in South America, most of this in the Amazon Basin. Based on these estimates, an area of tropical forest large enough to cover North Carolina is deforested each year!

The rate of deforestation varies from region to region. Recent research results showed that in the Brazilian Amazon, the rate of deforestation was around 6200 square miles per year from 1978-1986, but fell to 4800 square miles per year from 1986-1993. By 1988, 6% of the Brazilian Amazon had been cut down (90,000 square miles, an area the size of New England). However, due to the isolation of fragments and the increase in forest/clearing boundaries, a total of 16.5% of the forest (230,000 square miles, an area nearly the size of Texas) was affected by deforestation. Scientists are currently analyzing rates of deforestation for the current decade, as well as studying how deforestation changes from year to year.

The much smaller region of Southeast Asia (Cambodia, Indonesia, Laos, Malaysia, Myanmar, Thailand, and Vietnam) lost nearly as much forest per year as the Brazilian Amazon from the mid-1970s to the mid-1980s, with 4800 square miles per year converted to agriculture or cut for timber.

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Tropical Deforestation
Why Deforestation Happens
The Rate of Deforestation
Deforestation and Global Processes
After Deforestation