Gaviotas is a relatively famous eco project. It has been going since the early 1980's. They began planting a Caribbean pine tree in the otherwise barren llanos of eastern Colombia.
The presence of the forest has altered the local climate by generating
an additional 10 percent rainfall, which also supports Gaviotas' water
You can read more about them here:http://www.friendsofgaviotas.org/Friends_of_Gaviotas/Home.html