In the southern Mexican state of Chiapas, thousands of hectares of tropical forest have been destroyed in the last hundred years. Timber companies, followed by ranchers and coffee producers, converted biologically diverse, soil-protecting forests into barren and desiccated landscapes (O'Brien 1997). Additional destruction of forests has accompanied the search for petroleum resources in the region and an influx of impoverished refugees from Central America and migrants from other parts of Mexico seeking farmland (Gonzalez-Pacheco 1983).