The bristlecone pine is the longest-living thing on Earth. These trees, with their strangely shaped, wind-beaten limbs, can live up to 5,000 years. But experts worry that a warming climate in some areas may threaten its future. Researchers say warmer weather is permitting a similar kind of tree, the limber pine, to take over good growing places from the ancient bristlecone. They say the tree is being crowded out of mountainous areas where it grows. Scientists at the University of California, Davis, compared the competing species to two old men in a very slow race up a mountainside. This race between such slow-growing trees takes thousands of years. They say climate change is causing the competition. Brian Smithers led the research project. His team worked with the U.S. Forest Service to study the trees. “Limber pine is taking all the good spots,” he said.