LiveScience: A raging forest fire sweeping toward Yosemite National Park in California may threaten giant sequoia trees. The massive Rim Fire is an intense "crown" fire, meaning it is burning and leaping in the tops of trees instead of crawling along the ground. The National Park Service has closed two of Yosemite's three giant sequoia groves to work on preventive fire efforts, a park service statement said. The Merced and Tuolumne groves are about 4 miles (6 kilometers) from the edge of the Rim Fire, which...