Limber and Bristlecone Pines Healthy in Great Basin National Park

Two white pines

Great Basin National Park has two white pine species:

• Limber pine grows across the widest range of elevations of any North American white pine — from low sites to treeline — and in many kinds of environment.
• Great Basin bristlecone pine grows high up and lives extraordinarily long: some individuals are more than 5,000 years old, among the oldest living things on Earth. Park staff list it as a species of management concern.

Both face the same threats: mountain pine beetles, a warming climate, and white pine blister rust, caused by a non-native pathogen.

Good news

The Mojave Desert Network began monitoring both species in the park in 2018 and finished installing its last plots in August 2020. Sampling alongside staff of the Upper Columbia Basin Network — who monitor limber pine in Idaho — scientists found the trees healthy, with no sign of blister rust.

Why they matter

These long-lived high-elevation pines are foundation species. They:

• grow where conditions are too harsh for other trees, creating stable pockets that other species depend on;
• help regulate snowmelt and streamflow;
• let shade-tolerant plants take hold;
• feed and shelter birds and mammals — Clark's nutcrackers, jays and chipmunks eat and spread their seeds.

Lose a foundation species, and a cascade can follow: shifts in biodiversity and in how the community functions and holds together.

The threats

White pines are declining in many subalpine forests, especially in the Rocky Mountains and Cascades.

• Blister rust: the non-native fungus Cronartium ribicola infects five-needle white pines. It girdles branches and trunks, cutting off nutrient flow, and causes cankers in the bark that leave trees open to bark beetles.
• Mountain pine beetle: a native insect with periodic outbreaks — but recent epidemics in high western forests are unprecedented in length and scale.
• Warming: higher temperatures let beetles thrive at higher elevations, and for longer each season lower down.

What monitoring asks

• Are white pine forests changing in structure and species mix?
• Are tree deaths rising, and are fewer seedlings appearing and growing into trees?
• Are the key disturbance species — invasive Cronartium ribicola and native mountain pine beetle and dwarf mistletoe — becoming more common or severe?

What it's for

• Early detection of disease, damage or decline, so managers can respond in time.
• Sharing the importance and condition of these trees with visitors, which enriches their experience and helps protect the ecosystems.
• Combining data with other networks and parks across the western U.S., so managers can solve problems together.

More: a two-page project overview.

Sources

Based on "White Pines Healthy in Great Basin National Park," National Park Service; a work of the United States government in the public domain.