Home News Local News Sumpter Valley native studies grazing effects on dredge tailings
Sumpter Valley native studies grazing effects on dredge tailings
By Terri Harber
Dallas Defrees recently spoke to Baker County officials about how grazing improves previously mined soil.
Defrees, a Sumpter Valley native, based her presentation on her recent Honor College thesis titled “Using Cattle as a Tool: Restoring the Sumpter Valley Dredge Tailings."
Her family owns Defrees Ranch LLC. They lease adjacent land from Baker County in the dredge tailings for cattle grazing.
Defrees, an Oregon State University graduate, studied the long-term effects of grazing on the 50-acre section in the southeast side of the tailings.
In May she defended her thesis to university officials — an experience she described as “more nerve-wracking” than her Powerpoint in front of a hometown audience.
“I enjoyed both opportunities to share the results that I found and talk to people about the restoration,” she said.
Defrees earned her honors Bachelor of Science with a major in biology and a minor in chemistry magna cum laude from OSU this spring.
She was Baker High School’s class valedictorian in 2009.
The Sumpter Valley was once filled with “grassy meadows that ranchers utilized to graze cattle and build homesteads,” she wrote.
Miners dredged gold there from 1913 to 1954.
The practice “dramatically changed the landscape of Sumpter Valley, Oregon into rocky, uninhabitable terrain.”
There were three operations on 2,500 acres during the four decades that yielded $10 million in gold.
The dredge company exited the area “as quickly as possible, with little or no cleanup” in 1954 because that year it lost more than $100,000. Old cables and dredge parts still litter the ground and can prove harmful to animals, people and farm equipment.
Over the years weeds sprouted and, eventually, “infested the rest of the valley,” Defrees said.
The Oregon Department of Fish and Wildlife took over the land during the mid-1970s.
Some of the leftover dredge ponds were stocked with trout but those efforts failed. And the amount of hound’s tongue, mullein and knapweed only increased.
Baker County created the Sumpter Valley Dredge Use Plan in 1979 and revised it in 1984. Little else was done to the land for more than a decade, she said.
Defrees described the dredge tailings as an “eyesore” when looking out at it from her family’s ranch. Weeds started coming onto the ranch so her family needed to come up with a hands-on solution.
In 1998, the Defrees Ranch entered into a lease agreement with the county for cattle grazing on a little more than 10 acres. The family saw the partnership as a way to “gain land for winter feeding and summer grazing.”
Three years of wintering cattle brought positive changes.
“The experimental 10-acre plot provided substantial evidence of improvement,” Defrees said. “There was an increase in organic matter and vegetation.”
The Defreeses then leased 40 more acres immediately northwest of the first 10 acres. After contouring the site, cattle feeding and grazing commenced.
The overall management goals of this project were to control the noxious weeds; make the area look better; and help the soil produce grasses and legumes with seeding and fertilization.
Their practices “show that this restoration method has been successful,” Defrees said. “The continuation of it will persist in increasing the value of land and provide needed vegetation for a highly distressed land.”
Defrees conducted several tests and made observations on designated plots of land — some of which served as control sites.
The land was seeded with grasses and the cattle grazing controlled. Reports about these activities also provided information to provide a time line that chronicles how changes occurred over nearly 20 years.
Random soil samples were taken to see whether organic matter proliferated. Development of topsoil was important as well because both are needed to foster plant growth.
The amount of usable forage was measured and the species identified.
Photographs taken during the years by the family captured evidence of progress.
Feeding the cattle hay provided hoof action, consumption of vegetation, and waste products that ultimately improved soil conditions.
“Cattle are often accused of destroying land through over grazing, trampling of vegetation, etc.,” she said. “In this case all of these actions were desired and resulted in positive outcomes.”
Soil analysis showed that the nearly sterile conditions that existed after dredging ended evolved into a “healthier, more productive environment,” because of her family’s and the county’s efforts, Defrees said.
The coverage of bare ground decreased by 73 percent, and biomass increased by more than 300 percent.
Plant species diversity not only improved but included more perennials.
Wildlife became more commonplace to this portion of the dredge tailings as well.
“Elk really love to live there,” she said.
The populations of cottontail rabbits and snowshoe hares increased. This, however, drew hungry predators — specifically cougars and bobcats.
As a result, “the cattle went berserk,” she said.
The county renewed its Sumpter Valley grazing leases in March with the Defrees and Warnock ranches to control noxious weeds. These are five-year agreements.
There has been some renewed interest in trying to extract gold potentially remaining in the ground. The acreage Defrees highlighted in her thesis also is within the area that could potentially be mined again.
“Both historical and current practices continue to put an emphasis on a quick profit with little reflection on future impacts,” Defrees concluded in her thesis. “However, it is promising to see that the restoration projects have the ability to return land to a more sustainable and valuable state.”