Washington — If you’ve ever taken shelter beneath a tree during a rainstorm, you may have noticed water trickling down the trunk of the tree. It’s one of several water conservation jobs Mother Nature assigned to trees.
To understand the importance of trees to water, consider this: 100 mature tree crowns can capture 380,000 liters of rain in a year. By regulating water for the world’s great rivers, trees secure water quality and supply water for close to half of the world’s largest metropolises — including New York City.
So in a world where access to safe drinking water is a daily challenge for hundreds of millions of people, trees are absolutely critical. Not only do they help collect and filter water for local aquifers and watersheds, they also help prevent flash floods and runoff that pollute waterways and worsen droughts.
In parts of East Africa, decades of illegal logging and clearing of land contributed to devastating droughts in recent years. In Kenya, a country that depends on hydropower for two-thirds of its electricity, droughts have also had a direct effect on energy supplies and, by extent, the entire economy. Organizations such as the U.S.-based Nature Conservancy are now partnering with the Green Belt Movement and other local conservation groups to encourage tree planting in sensitive watersheds that sustain rivers.
Trees have another important job: They create more rain.
Forests help regulate water through a process called transpiration. After absorbing water through their roots — one tree can suck up thousands of liters during its lifetime — trees carry the water up through their trunks and into their branches and leaves. Whatever water is not used by the tree is then released back into the air.
When the air becomes saturated with moisture from the trees, rain clouds form. The process is called the “cycle of water.”
