Forests can fall to the need for timber, population growth and clearing for agricultural land, but deforestation changes natural habitats and creates several human health concerns. Even an increase in infectious diseases, depression, and alcohol abuse can result from deforestation and the disruption of habitats and of cultures. Reports from Southeast Asia say that deliberately set fires have increased pollutants in the air that cause respiratory problems and contribute to global climate change. Deforestation may continue at high rates until more of us see the value of forests for bio-diversity, potential medicines, improved environmental quality, and climate mitigation. In New York and New Jersey, forest lands have been purchased to preserve the watershed and ensure quality drinking water; instead of building water treatment plants. The US Department of Agriculture used popular trees to decontaminate soil pollutants.