ScienceDaily: Regrowth of trees explains why grasslands in western Africa known as the Sahel have recovered after devastating droughts in the 1970s and 1980s, according to South Dakota State University professor Niall Hanan. The Sahel is a semiarid region with grasslands and scattered trees sandwiched between the Sahara Desert to the north and tropical savannas to the south.
Hanan, a senior scientist at the Geospatial Sciences Center of Excellence, and colleagues postdoctoral research associate Armel Kaptué...