Fire Suppression, Drought Increasing Mortality Among Trees

An Oregon State University forester says dry winters and long periods of drought, combined with fire suppression, are affecting the health of Central Oregon trees.

Nicole Strong, a forestry and natural resources extension agent for OSU, described an increased amount of tree mortality _ including junipers _ in Deschutes, Crook and Jefferson counties.

The Bulletin reports that Strong says junipers on the High Desert have become more fragile in recent decades, thanks to fire suppression policy. Periodic fires thin forests and improve the health of existing trees. When fires do not occur, forest density increases, resulting in more competition for water and space to grow.

“This is the main reason we see a lack of resilience and mortality during periods of drought, as well as when there are insect or disease outbreaks,” she said. “If nothing is done, such as prescribed burns, this will be compounded in the future according to climate change models.”

The tree deaths have also been noticed by the Bureau of Land Management, which manages thousands of acres of juniper woodlands in Central Oregon. Deschutes Field Manager Jeff Kitchens described dying junipers in the High Desert between the Bend Airport and Powell Butte, as well as Crooked River Ranch.

“I am getting calls from landowners regarding trees on adjacent public lands and we wish we could provide an answer. People are noticing the dying trees and we are directing them to reach out to local extension offices,” Kitchens said.

Juniper trees typically grow between an elevation of 2,600 and 9,800 feet and can live up to 1,600 years. Their berry-like cones, 5-10 millimeters in diameter, are an important source of food for birds native to Central Oregon, including Clark’s nutcracker and the American robin. Native Americans used the berries for medicinal purposes.

The BLM has no imminent plans to remove dead trees.

“If at any time areas affected were to directly be safety hazards to human life and or property we would work with our partners and neighbors to prioritize treatments. Some mortality, which may be a natural process of thinning and forest/woodland succession, will most likely benefit the ecosystem and require little, if any, active management from us,” Kitchens said.