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Individual Highlight

More Scotch broom found where logging debris was removed

Woody debris after logging was removed at the site above; 3 years later Scotch broom, a nonnative invasive shrub, covered 26 percent of the area, whereas it covered 6 percent of the area when logging debris was left on site. Tim Harrington, Forest ServiceSnapshot : Scotch broom, a nonnative, invasive species, is a severe competitor of young Douglas-fir.

Principal Investigators(s) :
Harrington, Timothy B., Ph.D. 
Research Station : Pacific Northwest Research Station (PNW)
Year : 2011
Highlight ID : 341


A scientist with the Pacific Northwest Research Station and partners in the forest industry conducted a study to see if the presence or absence of logging debris affected planted Douglas-fir and associated vegetation. Their study sites included areas where only harvested logs were removed, leaving behind branches and treetops, and areas where all branches and treetops were taken off site.

They found that intensive forest harvesting practices that remove most of the logging debris will increase abundance of Scotch broom. Three years after debris was removed, Scotch broom, which was present in the understory prior to forest harvesting, covered 26 percent of the area, whereas it covered 6 percent of the area where debris was retained. In the fourth year after the debris treatments, survival of planted Douglas-fir was lower where debris was removed (62 percent) compared to where it was retained (79 percent). This information will help land managers increase productivity of forest plantations by reducing the negative, indirect effects of debris removal.

Forest Service Partners

External Partners

  • Green Diamond Resource Company, Virginia Tech

Program Areas