Amazon forest could disappear, soon.A new computer model that includes a forest's effect on regional climate shows that the Amazon rain forest could disappear much more rapidly than previously expected. Rain forests depend on large amounts of precipitation precipitation, in chemistry precipitation, in chemistry, a process in which a solid is separated from a suspension, sol, or solution. In a suspension such as sand in water the solid spontaneously precipitates (settles out) on standing. to remain lush. Much of the moisture taken in by a trees' roots returns to the atmosphere through the leaves in a process called transpiration transpiration, in botany, the loss of water by evaporation in terrestrial plants. Some evaporation occurs directly through the exposed walls of surface cells, but the greatest amount takes place through the stomates, or intercellular spaces (see leaf). . In the rain forest, this process has a significant effect on local and regional climates, says James E. Alcock, an environmental scientist at Pennsylvania State University's Abington College in Abington. Logging and burning for agriculture currently claim about 1 percent of the Amazon rain forest per year. Alcock says that this large-scale deforestation deforestation Process of clearing forests. Rates of deforestation are particularly high in the tropics, where the poor quality of the soil has led to the practice of routine clear-cutting to make new soil available for agricultural use. substantially alters the rate of transpiration. After farmers and loggers cut and burn broad swaths of rain forest, more precipitation runs out of the area via the rivers. This leaves less moisture to return to the atmosphere--and that means, in turn, less rain. As a result, forest areas that people have cleared don't grow back as quickly. Meanwhile, the decrease in precipitation slowly transforms the remaining stands of trees into a different type of forest. Because large-scale deforestation of the Amazon River Amazon River Portuguese Rio Amazonas River, northern South America. It is the largest river in the world in volume and area of drainage basin; only the Nile River of eastern and northeastern Africa exceeds it in length. basin began in the mid-1970s, a simple calculation that accounts for regrowth Re`growth´ n. 1. The act of regrowing; a second or new growth. The regrowth of limbs which had been cut off. - A. B. Buckley. predicts that the rain forest there will last only until 2150 or so. However, Alcock says that when mathematical models
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