Impact of Western Juniper on Impact of Western Juniper on Hillslope Hydrology: Hillslope Hydrology: Steens Mountain, ORSteens Mountain, OR

Eastern Oregon Agricultural Research CenterBurns, OR

Northwest Watershed Research CenterBoise, Idaho

BackgroundBackground

• 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 InfoProject Info

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

Vegetation ResponseVegetation Response

Cut plot Un-cut plot

Trough WaterTrough Water

Cut plot Un-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

ConclusionConclusion

• 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?Questions?

For more information contact:

Jon Bates or Tony Svejcar

(541) 573-8900

or

Fred Pierson

(208) 422-0700.