Subalpine sentinels: Understanding & managing whitebark pine in California

A hardy inhabitant of the subalpine zone of western North America, whitebark pine (Pinus albicaulis) is a keystone tree species in California’s subalpine forests, where it regularly defines the upper treeline in the Sierra Nevada, Cascade, Warner, and Klamath Mountains. Walking portions of the John Muir Trail in the southern Sierra Nevada, moving through extensive stands and mats of whitebark, one might wonder why such an apparently widespread and hardy species would be under consideration for listing as a federally endangered species.