The right tree for a dry place

Abstract

Ever increasing water scarcity across the world has triggered a heated debate: Does planting trees ease or worsen water shortages? Last year, an article in the Economist , quoting research from the University of Newcastle, in Britain, and Free University in Amsterdam, argued that planting trees can exacerbate droughts. Scientists at the World Agroforestry Centre claim that this is only one side of the story. “Trees are not bad, but it has to be the right tree in the right place,” says Prof. Chin Ong, principal scientist at ICRAF. The Centre’s studies show that integrating trees into agricultural systems can increase the efficiency of water use, while plantations of fast-growing evergreen trees can worsen water shortages. These findings, based on 20 years of research by ICRAF in the Kenyan drylands, are part of a new policy series on the role of trees in watershed management