Environment News Service: Forests in the interior western United States, the southwest, and Alaska are already being affected by climate change with increases in the size and frequency of forest fires, insect outbreaks and tree mortality. These changes are expected to continue, according to a new report issued Thursday by the U.S. Climate Change Science Program. The Climate Change Science Program integrates the federal research efforts of 13 agencies on global change change. The U.S. Department of …