Forests' Retreat: Page 3 Endangered Species Handbook

Forest

Forests' Retreat: Page 3

In the year 1500, tropical forests covered continental and island areas totaling 5.5 million square miles (Collins 1990). Today, only a fraction of this extraordinarily rich ecosystem remains. The estimates of loss vary. Some scientists count only the acreage of untouched pristine rainforest in their estimates, while others include various types of tropical forests, second-growth and disturbed forests. Satellite images, combined with aerial photography and ground surveys, are giving an ever more detailed and accurate picture of the decline of these irreplaceable forests. One reference, The Last Rainforests, edited by Mark Collins (1990), calculated that in 1990, only 3.3 million square miles of tropical forest remained in the world. It estimated that about 54,000 square miles were being cleared worldwide every year (Collins 1990). This authority concluded that 50 percent of all tropical forests had been lost since 1900 (Collins 1990). In the disastrous decade of the 1990s, as much as half of the remaining tropical forests were cut or burned. Although estimates of loss vary, there is general agreement that dramatic losses occurred in many parts of the world during the 20th century.

This destruction is taking place at a catastrophic rate. According to Dr. Edward O. Wilson of Harvard University, an expert in biodiversity and tropical forests, the surviving tropical forests equal the lower 48 US states in area, and a region the size of Florida is disappearing each year. The Nature Conservancy (2000) estimates that 40 million acres of tropical forests disappear every year. Settlers in many tropical forests have traditionally practiced slash-and-burn. The soil is so thin that it becomes sterile after a few years of farming, and the farmers move on, cutting more forest. Such practices whittle away at forests, but when carried out only by small bands of natives, these cut-over acres tend to recover in time. In many areas, however, European settlers have cleared land in this manner and fertilized the soil, maintaining it as agricultural land or depleting it so severely that the forest can never grow back.