Exotic plant species respond to timber harvest in ponderosa pine forest

Photo Credit

Forest Service photo by Jack Butler

Understory plant community of Ponderosa Pine forest seven years-post-timber harvest on the Black Hills National Forest.

Forest managers have continued challenges with exotic plant species following timber harvest. Scientists are studying understory responses for seven years after timber harvest across ten timber sales on the Black Hills National Forest. 

They found that with low levels of exotic species abundance before harvesting, understory exotic species abundance increases with timber harvest intensity. However, understory plant communities with high levels of exotic species abundance before harvest may or may not experience increases in exotic species abundance after timber harvest. Changes in post-timber harvest exotic species abundance typically stabilize two years following timber harvest.

Managers can expect highly variable exotic understory plant community responses at sites with a pre-harvest exotic species composition greater than 20 percent. However, they can plan for increased exotic plant species abundance with increasing timber harvest intensity at low pre-harvest levels of abundance. 

This project focused on understory responses for seven years after timber harvest across ten timber sales on the Black Hills National Forest. This forest produces a large amount of the timber for Region 2 and the Forest Service and timber harvest there occurs frequently.