Threats to Oregon's forests


Oregon is a great place for growing trees, especially conifers like Douglas-fir. However, our forests are vulnerable to multiple threats, including wildfire, insects and disease. One of the keys to creating forests that are resistant to forest threats is active forest management designed to improve forest health.

Historically, wildfires were frequent in dry-side forests, sometimes burning every five to 20 years. But we’ve worked to keep fire out of these forests for over 100 years. Now instead of 20 to 40 big trees per acre, forests often have more than 1,000 small and medium trees per acre and are prone to larger and more damaging wildfires. One way to combat the threat of wildfires is active forest management such as thinning or prescribed burning.

Insects are another big threat to Oregon’s forests, especially the dry forests of southern, central and eastern Oregon. Bark beetles often kills trees that are already under stress from overcrowding, drought, disease or fire. One way to combat the threat of bark beetles is to thin an overcrowded forest or, better yet, thin a forest before it becomes overcrowded. This provides more water and nutrients for the remaining trees, reducing their stress and susceptibility to a bark beetle attack.

A common threat to western Oregon forests is tree disease. Root rots are diseases affecting thousands of acres. Root diseases attack and kill a tree’s root system, hindering its ability to take up water and nutrients from the soil and reducing the support. Infected trees also grow more slowly and are more likely to blow over in wind storms and die. Fortunately, not all tree species are susceptible to the same root rots. Thinning to favor less-susceptible species and replanting with these same species after timber harvest can reduce the threat of root rot in our forests.

These are only three of the many threats facing Oregon’s forests. Other threats include invasive species, weather, climate change and people. To learn more about the threats to our forests, visit This page features a new special report titled Forest Threats: Active Forest Management – Protecting Oregon’s Forests for Future Generations. It also includes a series of five videos that cover fire, insects, disease, invasive species and weather.

For the forest,

Mike Cloughesy

Director of Forestry



9755 SW Barnes Rd., Suite 210        
Portland, OR 97225        
Phone: 971-673-2944        
Fax: 971-673-2946

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