LAKE TAHOE, Nev./Calif. – The UC Davis Tahoe Environmental Research Center is studying how to restore whitebark pine, one of the Tahoe region’s most vulnerable trees.

These trees grow in high, remote regions of Lake Tahoe and face a number of mounting pressures, from drought and bark beetles to an invasive disease that kills cone-producing branches. Called white pine blister rust, the disease is particularly concerning because without cones, there are no seeds, and without seeds, there are no future generations of trees, spelling impacts beyond the species itself.

“A healthy lake starts with a healthy watershed—including the forests surrounding it,” TERC said in its update on the study.

TERC’s forestry team, including Camille Jensen, Aaron Vanderpool, Shannon Lynch, and Patricia Maloney, is conducting two projects that may help land managers protect the species’ surviving populations and restore forests after wildfire.

The projects ask two vital questions:

• Which trees offer the best hope for future generations?
• What is the most effective way to help those generations grow?

The team is working to answer these questions by learning from trees that are currently thriving. Although certain populations on Tahoe’s north and east side are struggling, populations south appear to be healthy.

TERC is deciphering why some regions are struggling while others thrive and hopes to turn those differences into guidance for restoration.

The study involves measuring soil moisture, tree activity and water-use efficiency, what TERC calls tree “vitals.” The data provide insight into tree health. 

Researchers are also looking into whether the timing of when trees open their pores may play a role in withstanding blister rust infection. 

“If trees slow their activity and go dormant before spores arrive, they may be less vulnerable,” TERC’s update explained.

TERC’s team is also conducting a project in the Caldor Fire scar to test whether whitebark pine can be restored through planting seeds directly in the ground. Researchers planted seeds in the fall of 2024 from nearby whitebark pine families. They then placed small cages to protect the seeds.

If the study shows promising results, it could offer a quicker and more affordable approach to restoration because planting nursery-grown seedlings in remote mountain terrain takes considerable labor, equipment, and time, TERC says.

“Early results are encouraging: seeds have germinated, seedlings are surviving, and most cages have held up through the snow,” TERC said.

The team now plans to plant nursery-grown seedlings to compare survival.