Once upon a time, Yemen had rich areas for growing grapes, pomegranates, oranges, and the famed Yemeni coffee. Then came oil in Saudi Arabia and Yemeni men flocked there for work. The women cut trees for firewood and the terraces eroded for lack of maintenance. Water which once could be found at 60 meters is not found until 850 meters or more. Now Yemenis fight over water. See "Postcard from Yemen", Thomas Friedman, New York Times, 2013-05-08.
"Trees have the deepest system of root in soil. They evaporate water from sometimes 50 meters deep level of soil. It increase humidity in air and probabilities of rains, dew-sources of water." Comment by mioffe2000 in response to "Postcard from Yemen".
This comment got me thinking about "The Man Who Planted Trees" about a shepherd who planted acorns over a wide area that had been deforested by charcoal burners. The land was dry and suitable only for grazing sheep.
According to http://en.wikipedia.org/wiki/The_Man_Who_Planted_Trees, the story is a work of fiction. However, people all over the world have planted millions of trees in many countries to stop desertification and alleviate global warming. This article mentions a few of these projects.
What would the effect be on world peace if the U.S. exported cones instead of drones to some of the trouble spots of the world. Well, not exactly cones because evergreens are not suitable for many areas. Actually, for a small fraction of the military budget, the U.S. could send teams to plant trees of any size, from seeds to semi-mature trees a few meters tall. It would take a few years to bring better rainfall back to areas where water is scarce. More available water would reduce tensions among various groups and go a long way to reducing the hold terrorists have on some areas.
