My friend just told me about this - the original trees had tap roots that went 100's of feet down to water. The held the moisture in the soil so the younger trees could grow. When the area was clear-cut the hot sun burned away any new growth and the monsoons washed away the topsoil. It is now being re-greened through trial and error.

http://www.auroville.org/environment/env_introduction.htm

Nice to hear news about Aureville, I visited many farms there a decade ago. Tough, tough area with a very harsh climate, yet people really are restoring the land there in a very wonderful way. The progress is slow and hard, but the people are committed and educated, and their labors are rewarded. Smile on Aureville.