Due to increases in human population, there are many threats to the ecosystems of the Sierra Tarahumara Occidental region. The government funding to build a "tourist friendly" atmosphere poses threats to the environment and indigenous cultures. Roads have been built in the former isolated mountainous zones. Agriculture and grazing as well as the cutting of hardwoods and other trees for firewood has accelerated a soil erosion problem. Mesquite ("Prosopis" spp.) and desert ironwood ("Olneya tesota") trees are cut and exported primarily to the U.S. for charcoal. Amapa ("Tabebuia chrysantha") trees yield highly prized lumber for building and furniture making. Other trees are also cut and sold for their high-priced lumber. Over-harvesting of the forests in the area has caused the extinction of the imperial woodpecker and Mexican wolf. Approximately, two percent of the original old-growth forest remains. However, a massive forest-harvesting project in the region has been abandoned, for now, by the World Bank. The Mexican forestry department deemed these species of trees "legally protected," but enforcement is difficult.