Sequoia National Park has been shut down and its namesake gigantic trees are potentially threatened as forest fires burn in steep and dangerous terrain in California’s Sierra Nevada. Two fires were ignited by lightning last week and their combined sizes cover nearly 5 square miles on Tuesday. Both fires are projected to advance in the direction of Giant Forest, which is home to more than 2,000 giant sequoias. A park spokesman says Giant Forest is not imminently threatened but that there is a potential threat.