California continues to suffer under a historic drought. The state has received very little rainfall over the past four years.California is famous for its huge sequoia trees. They are among the largest and oldest living things on Earth.But scientists say the trees are suffering because of the lack of water.Now the National Park Service is studying how the drought has affected the sequoias and what can be done to help them survive.Anthony Ambrose is a tree biologist with the University of California, Berkeley.One recent day, he slowly climbed up a giant sequoia in California's Sierra Nevada Mountains. The Sierra Nevada range is the only place on earth where sequoias live."It's an amazing experience to be able to climb up into these things and know that it's been growing in this same spot for you know a thousand years or more."Sequoias can grow to a height of over 90 meters tall. The bottom of the tree can be up to 15 meters wide. Some trees are more than 3,000 years old.
