A quarantine will be placed on firewood, soil and plants from coastal regions to prevent sudden oak death in Yosemite National Park. Park officials are telling visitors from the San Francisco Bay area and points north they should clean soil and mud from shoes, bikes, and vehicles before traveling to the park. Firewood should not be brought to the park from those areas. Sudden oak death has killed tens of thousands of California´s prized live, tan and black oaks. It has also spread to other trees and shrubs, including maples, buckeyes and bay laurels. Those trees are found in nearly a quarter of Yosemite´s forests and two-thirds of its developed areas.