 Today, we're near Powder River Pass in the Big Horn Mountains. Behind me stands a limber pine. These trees are hardy. They'll establish on dry, windblown sites where other trees won't grow. In fact, once limber pine is established, it can create milder conditions where other tree species can grow. Whitebark pine, a close relative of limber pine, grows at higher elevations in even harsher conditions. Most species have five needles in a bunch, big cones, and big seeds. The seeds of limber pine and whitebark pine are highly nutritious. That makes them a delicacy to animals like squirrels, birds, and grizzly bears. A grizzly bear will smell and dig up pine nuts buried under six feet of snow. Unfortunately, these pine trees are facing a serious threat. It's called blister rust. This fungus isn't native to North America, so the trees haven't developed any resistance. They become infected and die. Researchers are working to find ways of controlling the spread of blister rust so we don't lose our limber and whitebark pines, which are so valuable because of their ability to grow on harsh sites and provide food for wildlife, especially grizzlies. From the University of Wyoming Cooperative Extension Service, I'm Zola Ryan.