Existing water flows are significantly hampered

Nov 9, 2009 07:38 GMT  ·  By
Newly planted forests can drastically alter the base flow of a certain region
   Newly planted forests can drastically alter the base flow of a certain region

In a new series of studies, experts have determined that planting new trees, and creating forests, in areas that previously had none, can have negative, long-term side-effects on the water flows of the region. This type of research is extremely important for policymakers, especially considering that the fight against global warming will hopefully call for the plantation of a large number of trees in the very near future. The papers suggest that this type of action will have to be made exercising extreme caution.

Trees are natural sponges when it comes to absorbing atmospheric carbon dioxide (CO2), experts say. The leaves collect the gas, and then, through the process of photosynthesis, convert it into oxygen and energy, using sunlight as a catalyst. Thanks to this ability, trees are among the preferred methods of fighting against global warming and climate change. Huge forests may do more to clean the planet than all reductions made in fossil fuel power plants around the world, some estimate. But experts cannot risk addressing a problem, and causing another one in its stead, Nature News reports.

In two new papers, scientists have proven that planting numerous trees in areas that previously had none may result in a diminished water flow for the region. The process is called afforestation, as opposed to deforestation, when trees are cut down. A team of investigators has determined that the base flow of the areas that received trees – a concept that refers to the amount of water not directly attributable to rain or glacial meltdown – diminished by more than 50 percent. The base flow is usually the measure on which the minimum necessary demands of the population in a certain region are calculated.

“It's a concern especially in drier regions, where the differences in base flow may be more noticeable,” Ban Binkley, a Colorado State University expert specializing in forest ecology, says of the potential differences. He has not been involved in the new study. The new finds were presented in Buenos Aires, Argentina, last month, at the World Forestry Congress. According to the papers' conclusion, the best balance between afforestation and ensuring water supplies is planting between 400 and 500 trees per hectare in river basins.