Great Basin National ParkThousands of feet above the Nevada desert, in a part of Great Basin National Park that tourists rarely see, park ecologist Gretchen Baker neared the top of Mount Washington and raised her binoculars. There just below, sprouting directly from the limestone, grew some of the oldest living things on Earth.

Great Basin bristlecone pines, their dense pale trunks twisted like thick rope by centuries of gusting wind and rain, thrive here in part because so little else does. At altitudes near 11,000 feet along Nevada’s rocky Snake  Range there are no grasses, no brush, few pests, no competition. No people to start wildfires. No nearby trees to spread pathogens.

With nothing around to kill them, these ancient beasts are left alone year