Researchers question long-term impact of planting forests
Researchers at Duke University are challenging the long-term impact of the accepted practice of planting forests in order to soak up carbon dioxide.
The Duke study says while the practice of planning fast-growing trees does, in fact, remove the gas from the atmosphere, side effects include the drying up of streams and depletion of the soil. Those changes, researchers say, might not be an equal trade-off for the tree-planting benefits.
The Duke team surveyed more than 500 places where new forests have been planted over the past half-century. According to their findings, 13 percent of those cases resulted in streams drying up completely for at least a year. On average, the tree "plantations" cut local stream flows by half. According to the Duke researchers, the planting of trees on land previously used as cropland reduced the available supplies of drinking and irrigating water.
Not all changes in water flow, however, are thought to be negative. U.S. agriculture officials say the forest plantations in the U.S. agricultural belt have prevented runoff from farmlands into the sea. That nutrient runoff has been credited with causing algal blooms that kill marine life.
The Duke University findings were published in the latest weekly edition of Science.