The massive flood of refugees from Afghanistan into forested areas of Pakistan's northwest frontier during the 1980s has led to major deforestation in what were once heavily forested regions, with certain cedar forests becoming totally decimated, says a UC Davis geographer. The devastation is so widespread that a temporary ban was placed on green-felling of trees late last year, prompted in part by the work of researchers including Nigel Allan, a UC Davis professor whose work was funded by the National Geographic Society. Based on both Geographical Information System computer analysis of satellite imaging and visual inspections, 42 percent of the standing trees appeared to have been removed from one vast forest between 1978 and 1989, Allan and his associates reported at a recent meeting of the Association of American Geographers. The deforestation leads to environmental problems, including siltation of the Tarbela dam, the largest source of power and irrigation water in northern Pakistan, and destruction of irrigation channels, Allan says.