Stable Plant Communities in the Pacific Northwest.

The application of stable low-growing plant communities as a tool in right-of-way (ROW) management is new in the Pacific Northwest. The development and use of this approach has been primarily in northeastern North America. We initiated a multi-year program to assess the application of this method to rights-of-way in the highly productive western hemlock zone of the Pacific Northwest. Working in the western Cascade Mountains of Oregon and Washington, we found a mix of deciduous and coniferous trees growing in established electric utility rights-of-way that had been treated 3 to 4 years earlier. To identify types of species that were effective in limiting regeneration of trees, we examined gap closure processes in rights-of-way where trees and tall-growing shrubs had been removed. We also examined the ability of some common low-growing shrub species to form dense thickets of vegetation. Gaps were most quickly closed by species capable of rapid horizontal spread through vegetative reproduction. Several of the common clonal shrubs found on the ROWs were also capable of forming dense thickets of vegetation. Thus, while there are necessarily differences at the species level between the western moist coniferous zone and the eastern deciduous zone, the importance of vegetative reproduction holds. [ABSTRACT FROM AUTHOR]