Utah Department of Agriculture and Food

Emery County Uses Invasive Species Mitigation Funds to Fight the Russian Olive Invasion

Utah’s War on Weeds is usually waged against grasses, plants and shrubs that are anywhere from a few inches to a few feet tall. But Emery County’s current assault, as part of UDAF’s Invasive Species Mitigation (ISM) Fund grant program, is against Russian Olive trees.

Russian Olives grow thickly along stream corridors and prevent access by livestock, recreational users and wildlife. Originally, tamarisk trees invaded the riparian areas. These trees transpire a tremendous amount of water, said Emery County Commissioner J.R. Nelson. They suck as much as 50-100 gallons of water a day per tree from rivers and creeks, according to Nelson. With an average of less than 10 inches of precipitation annually, Emery County cannot afford to lose that much water to a species that doesn’t benefit recreation, wildlife or agriculture. But when the county started aggressively removing the tamarisk several years ago, Russian Olives took over the landscape. Russian Olives also drain a lot of water from the water table, according to local officials.

While the county has been fighting Tamarisk and Russian olive invaders for more than 30 years, the infusion of ISM funds two years ago greatly accelerated the effort. Along with State of Utah participation, local and federal agencies, volunteers, and land owners have all participated with time and equipment to make the money go father.


Because of the size of the trees being removed, heavy equipment, such as backhoes and a special grinder/chipper are used to clear the trees. Piles of the removed trees are then burned. Finally, the area is sprayed several times over a 3-5 year period to kill any new trees trying to regrow.

While some areas are being reseeded by private landowners, most of the area will naturally regenerate with cottonwood trees and other native vegetation, once the invasive trees are gone. To this point, the county estimates that more than 120 miles of the San Rafael River and its four tributaries have been treated. The county has asked for additional ISM funds this year. Those grant decisions will be finalized by mid-June 2014.