Whitebark pines, Jasper National Park.

Whitebark pine trees on a rocky ridgeline, overlooking a valley carpeted by dense coniferous forest in Jasper National Park, Alberta. One whitebark pine tree, just right of centre image, is tagged with a small white pouch containing verbenone—a pheromone chemical that discourages mountain pine beetles from attacking. (The pheromone mimics the scent of other pine beetles, telling any new beetles to “move along because this tree is already occupied”. Verbenone is one useful tool that Parks Canada uses to help protect and conserve whitebark and limber pines.