Denude hills of trees and the result will be rainstorms triggering floods and mudslides, as both Haiti and the Philippines have had to learn again. More than 1,000 people died in each country during recent torrential rains.
Much of the blame goes to deforestation. Only 3 percent of Haiti is covered by vegetation now; people need wood for fuel. In the Philippines, not only do the poor leave hills eroded, but loggers - both legal and illegal - have put entire villages at risk of flooding.
An attempt by the Philippines to ban logging after last month's floods is laudable. But sustainable, regulated commercial logging will be nearly impossible in that tropical nation unless the graft that allows illegal loggers to ravage forests is tackled first. And foreign buyers such as Japan have voracious appetites for wood products, with plenty of cash to throw around.
This deadly cycle can be broken only by sustained political reform and tough international rules against buying timber through illegal loggers.