William Campbell Photography

Dead whitebark pine trees in Yellowstone National Park. The high altitude tress were killed by mountain pine bark beetles. Scientists have attributed the current pine beetle outbreak to climate change and warmer wintersDead and dying white bark pine trees killed by mountain pine beetles in Yellowstone National Park, Wyoming . The trees cones and seeds are an important food source for grizzly bears. Some many of the white bark pine tress have been killed by mountain pine beetles the Yellowstone grizzlies were returned to the endangered species list. Scientists have attributed the current outbreak of pine beetles to global warming climate change and warmer winters. The beetles have killed tens of millions of acres of trees in the Rocky Mountains of North America and Canada.