BLM Idaho works to conserve Whitebark Pine trees

This story has been updated to reflect USFWS final action on proposed listing under the Endangered Species Act (December 14, 2022).

BLM Idaho specialists use all the tools in their toolboxes to manage, protect, and restore the Whitebark Pine (Pinus albicaulis)—an iconic, high elevation keystone tree species that provides many ecological services in its habitat. BLM-Idaho manages a small, but ecologically important portion of Whitebark Pine’s range (less than 1% of the species’ total range) within the Challis, Salmon, Cottonwood and Coeur d’Alene field offices.

Since the early 2000s, BLM specialists have worked closely with specialists from the U.S. Forest Service and the Whitebark Pine Ecosystem Foundation to plan and implement Whitebark Pine restoration projects. BLM Whitebark Pine restoration projects are all the more important now, since in December 2022, the U.S. Fish and Wildlife Service listed the Whitebark Pine as a Threatened species under the Endangered Species Act, due to population declines from white pine blister rust (an invasive fungal pathogen), mountain pine beetle outbreaks, altered fire regimes and climate change.

In recent years, all four Field Offices have surveyed their high-elevation forests to evaluate Whitebark stand composition and health. The BLM specialists surveying the forests have discovered that there are more whitebark pine stands than they had thought. One of the first projects the BLM implemented was a study in the Challis Field Office involving verbenone, an anti-aggregating pheromone. This pheromone helps protect whitebark pine trees by inhibiting mountain pine beetles’ ability to mass-attack and overwhelm a specific tree. Stapling verbenone pouches to whitebark pine trees makes the beetles think that the trees have already been attacked, and they should move on to a different tree. The verbenone project was implemented in 2005 and concluded in 2012.

BLM specialists have also identified whitebark pine “plus trees” in the Challis, Cottonwood, and Salmon Field Offices. These are mature, cone-producing trees that have not been affected by blister rust—even though trees around them have. “Plus trees” appear to have some genetic resistance to white pine blister rust. Trained contract crews climb “plus trees” in the early summer and put mesh cages around cones to prevent Clark’s nutcracker and other animals from eating the cones. At the end of the summer, the tree climbers return to remove the mesh cages and collect the mature cones.

The BLM works with the Forest Service’s Coeur d’Alene nursery to plant the seeds and test the seedlings for genetic resistance to white pine blister rust. Blister rust-resistant seedlings are available for planting in areas where there is little natural whitebark pine regeneration, due to fire or excessive mortality from mountain pine beetle or blister rust.

Thinning treatments to reduce competition for Whitebark pine have been completed in the Challis Field Office and are planned in the Coeur d’Alene, Cottonwood and Salmon field offices. Whitebark pine is relatively slow-growing and shade-intolerant compared to other high elevation trees, such as lodgepole pine and sub-alpine fir. By removing non-Whitebark tree species, more resources are available for whitebark trees to grow and thrive.

Whitebark Pine is a unique tree. Two important ecological services are its large root system, which stabilizes soil and prevents erosion, and its large, nutritious seeds, which provide food to many bird and mammal species, including grizzly bears. Whitebark pine trees grow between 6,000-12,000 feet in elevation. It is a very long-lived species with some trees documented at over 1,000 years old.

BLM Idaho is excited to have the opportunity to help this species meet the challenges it is facing.


Bureau of Land Management

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