Salmon habitat restoration projects have reforested around 800 hectares in the Skagit River watershed
from 2008 to 2017 but coincident growth of the North Cascades Elk Herd has complicated these efforts.
Cervus canadensis (elk) browse terminal and primary lateral branches and wound bark on seedlings,
resulting in reduced growth, vigor and survivorship. This impacts restoration success and increases
reforestation costs. Few studies have compared the efficacy and shortcomings of methods to reduce C.
canadensis damage within a restoration setting. This study aimed to 1) compare the efficacy of paper
bud caps, companion planting with Picea sitchensis (Sitka spruce), and Plantskydd® topical repellent in
reducing C. canadensis browse; and 2) test the efficacy of Plantskydd® topical repellent in reducing bark
wounding on seedlings at the Savage Slough Restoration Project site near Concrete, Washington. We
found that Companion planting and Plantskydd® application significantly reduced browse damage,
whereas paper bud caps had no significant effect. Furthermore, Plantskydd® application did not
significantly reduce bark wounding. While Plantskydd® application or companion planting can reduce C.
canadensis browse in restoration plantings, thereby increasing success rates and decreasing costs,
Plantskydd® application is more expensive per hectare than companion planting.
Clifton, B.C. and Smith, D., 2018. Comparison of Deterrents to Reduce Elk Rubbing and Herbivory in a Skagit River Restoration Planting, Washington. Skagit River System Cooperative, La Conner, WA. pp. 10.
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