Drought Weakens Oregon's Conifer Trees

Oct 9, 2016

Oregon has seen record drought the last couple of years, and it’s taken a toll on the state’s conifers. But it’s not just water stress killing these trees—insects and disease that thrive in drier weather are just as deadly.

Credit Rachael McDonald

Christine Buhl is a state forest entomologist with the Oregon Department of Forestry.
She says even if we do pull out of a drought conifers may not fully rebound. Insects like bark beetles as well as certain diseases will still attack stressed trees.

Buhl: “Once bark beetles can overcome a tree’s defenses particularly in the case of a drought stressed tree, those beetles take residence and typically that tree will die within the year. Obviously there’s no rebounding from that.”

Buhl says healthy trees can create defenses against such threats; water stress weakens these protections. And dry weather means perfect conditions for tree-damaging insects.

However, Buhl says there are steps businesses and individuals can take. Select native, drought-tolerant species appropriate for the site and soil, and check with ODF for information on thinning and vegetation control.