Whitebark pine (Pinus albicaulis) is a critical forest species of Northern Rocky Mountain upper subalpine ecosystems, yet little is known about the physiological response of whitebark pine to disturbance (e.g., fire, bark beetles, and pathogens) across a range of diverse environmental gradients. Resin-based defenses have long been recognized as the primary mechanism by which conifers respond to attack by bark beetles and pathogens and several studies have linked resin duct properties to survivorship during periods of increased beetle activity. In this study, researchers compared axial resin ducts in the secondary xylem of whitebark pine across pairs of living and dead whitebark pine trees to better understand survivorship following multiple disturbances including mountain pine beetle and white pine blister rust. They found a clear distinction in growth and defense characteristics between live and dead whitebark pine across study sites on the Flathead Indian Reservation in northwest Montana.
Mountain pine beetles