Impact of Western Juniper on Hillslope Hydrology: Steens Mountain, OR Eastern Oregon Agricultural Research Center Burns, OR Northwest Watershed Research Center Boise, Idaho

Background 8.5 million acres in western juniper woodland 95% of the woodlands are 100 years old or less Juniper invasion results in  Significant reductions in shrub/understory production and cover  Reduced plant diversity  Loss of wildlife habitat  Increased erosion potential

Project Info Rainfall simulation plots were run on eight replicates of cut and uncut treatments.

Vegetation Response Cut plotUn-cut plot

Trough Water Cut plotUn-cut plot

Removing Juniper increases infiltration and decreases overland flow

Removing Juniper decreases runoff volume

Removing Juniper reduces sheet erosion

Removing Juniper decreases rilling

Junipers increase runoff and erosion

Conclusion Juniper invasion can result in a dramatic increase in runoff and erosion. The severity of erosion will likely be related to the loss of understory cover and the erosion potential of a site.

Questions? For more information contact: Jon Bates or Tony Svejcar (541) or Fred Pierson (208)