Western juniper is native on many arid rangelands. However, decades of fire suppression allowed these hardy trees to dominate vast areas, crowding out other plants. What’s more, these large populations of juniper negatively impact sage grouse habitat and can diminish sustainability of grazing land.

These trees pull more water from the ground than the grasses and shrubs around them. With increased demand for water by encroaching junipers, combined with several years of severe drought in some areas, the toll on springs and streams becomes more obvious. With loss of understory vegetation, soil loss during intense rain storms is greater.

Ranchers and range managers have been battling juniper encroachments for many years, according to Kyle Sullivan, district manager, Soil and Water Conservation District in Grant County, Ore. Several government projects have provided funding for mechanical removal—sawing down trees, piling and burning them. 

“That was one method, and some landowners had logging companies come in to remove them. The trees were not commercially viable, but this provided fill-in work for logging crews between jobs. They brought in their equipment to take out trees and had hand labor follow-up to go after the smaller trees,” Sullivan says. 

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The loggers piled them and the landowners burned those piles a couple years later after they dried out—during winter when there was no risk of fire danger. 

“One method still used in some parts of the West is chaining. A ship anchor chain with huge, heavy links is secured between two big Cat tractors and they go across-country and mow down the trees. The heavy chain uproots them,” says Sullivan.

Another method is to tip the tree over with an excavator boom. The machine then grabs it, picks it up, shakes the soil off the roots and piles the trees. It uproots the trees without much damage to the surrounding terrain. 

“This way you get some of the smaller branches underneath the soil; they pull up with the tree roots. It’s one of the more expensive alternatives but leaves a cleaner site.”

Chemical control

Sullivan’s Soil and Water Conservation District received grants to try to control juniper with herbicide. “About 11 years ago we did an experiment, using a method that required cutting incisions into the trunk with a chain saw, then squirting herbicide into the trunk with a spray bottle. Juniper is so bushy, however, that it’s difficult to get to the base of the tree,” says Sullivan.

“The crew tried different concentrations and different herbicides and it was effective, but the time and labor involved didn’t pencil out. The Forest Service preferred that method, however, because it left the dead trees standing in place, and didn’t tear up the ground or disrupt surrounding vegetation. It’s a way to kill some of the larger trees and keep them from reproducing,” he says.  

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“We’ve allowed a few live trees to remain on the landscape because they provide shade for livestock and wildlife, but they must be trees with no berries (seeds). Junipers have genders, and some trees have both male and female characteristics. If a tree isn’t producing berries it doesn’t spread seeds,” Sullivan says.

It’s important to continue maintenance after you remove or kill trees because the seed source is still there. The seeds are viable for a number of years and there will be new seedlings coming on. 

“You may get a new flush of young trees in seven to 10 years, so you need to do periodic controlled burning or go after those young ones with herbicide before they start reproducing, to eventually exceed the seed viability—what’s still there in the seedbank or spread by birds or other animals that eat the berries; the seeds go through the digestive tract to start new plants in new places.”

If junipers take over an area, they consume a lot of water that would have helped survival of other plants. “Research in central Oregon is looking at effects of hydrology, and how the canopy of these trees keep snow from coming to the ground. A large population of junipers has a negative effect on the watershed,” he says.

“Some people have started using herbicide pellets for control of juniper, and these seem to be beneficial,” says Sullivan.  There are multiple tools that can be used in battling woody species.

“We try to keep abreast of the research on these plants, and how to deal with them. Oregon State University has guidelines with advice on managing western juniper,” he says.

Rancher’s experience

Wilburn Ranches in Oregon is using chemical control of juniper invasions. Rich Wilburn used Pronone pellets on 200 acres last year with good results. He took photos of the trees afterward, showing how it killed them, and plans to do 400 acres next year. 

“I want to use it on larger trees and maybe increase the dosage on those that are fuller and have a bigger root system. The directions said to put one tablet on the ground in the drip zone of the juniper if it is 3 feet tall. Then for every additional 3 feet you put another tablet—up to about 10 feet of tree height. I’m going to increase the tablets and try to kill trees 12 feet or taller,” he says.

“I put these out in November or whenever moisture is sufficient to dissolve the tablet. I didn’t see any results until late June/July the following year. Then it was evident the trees were dying. The smaller ones seem to die all at once; larger ones die by degrees until they are all brown and dead,” says Wilburn.

“The cost per tree is small. That’s why I plan use a larger dose on the larger trees. Junipers in our region are taking over. It doesn’t take long before they are unmanageable and then you need chainsaws and Cats to get rid of them, making it very expensive. On our ranch, using herbicide pellets, we’ll probably have to do it every three to four years to keep the juniper contained.”

Mike Countryman, livestock fieldman at Northwest Farm Supply in Hermiston, Oregon, works with ranchers in five counties in Oregon and four in Washington, and says herbicide pellets provide an option for people who don’t want to mechanically remove trees by sawing them down or tearing them out and then burning them. 

“This product is used in the South on various woody plants. It’s not a new product, but we’ve just recently incorporated it here on our rangelands for juniper control, and it appears to be working,” he says.

It’s inexpensive and easy. “You just walk around and distribute the pellets, or ride around while you’re checking cattle and throw out the pellets from horseback. You just put them around the outside edges of the junipers,” says Countryman.

“Cutting them down or ripping them out, piling them up, is time consuming and expensive. With the little pellets you just drop them around the trees and anybody can do it. The rancher I hunt with plans to distribute them while we’re out there elk hunting. We never seem to shoot any elk anyway, so we might as well make our trip count! Perhaps a year from now we’ll have a lot of dead junipers.”

Smith Thomas is a rancher and freelance writer based in Salmon, Idaho. The opinions of the author are not necessarily those of beefmagazine.com or Farm Progress.