Burned area susceptible to invasive species
The scorched hillside from last summer’s Rendezvous Fire looms above the Rendezvous neighborhood north of Winthrop.
About 175 acres of shrub-steppe — a mix of sagebrush, bitterbrush, bunch grass and other native forbes — burned when a fire that started on private property spread into Washington Department of Fish and Wildlife (WDFW) land. The cause of the fire is still under investigation but it’s believed to be human-caused. The investigation should be released in December.
The Rendezvous fire was small compared to other burns in recent years in the Methow Valley, but it came within a few hundred yards of several homes and raised fears about fast-moving fires in sagebrush that can get out of control quickly.
Okanogan County Fire District 6, the state Department of Natural Resources (DNR), U.S. Forest Service and others fought the fire aggressively and contained it within a day. The response effort cost more than $130,000 and involved air drops of water and flame retardant, as well as bulldozed containment lines, mainly on the Cub Creek side of the blaze.
From a distance, the burn area now looks like a black slope of death surrounded by a strange red line of left-over flame retardant, but if you get up close you’ll see that new life is already taking hold as the brave, green shoots of grasses pop up after recent rains. The question is: what kind of new life do we want to see established after the burn? Local land managers are getting involved to help shape that.
Surviving the scorch
The Rendezvous Fire wasn’t particularly hot, compared to fires that burn in forests or landscapes with lots of downed trees and ground fuels.
“The native bunch grasses, they survive those fires real well,” said the DNR’s Ron Wonch, who has visited the burn area. “It’ll burn the tops off but the roots are still viable so they’ll resprout again. A lot of the sagebrush will do like the bunch grasses do. Their roots will survive and they’ll start sprouting again.” That could take several years, Wonch added.
“That fire moved quick,” said Brandon Troyer with the Methow Valley office of WDFW. “It was pretty flashy and it didn’t hit those big pockets of fuel like we saw with the large fires of 2014-15. It didn’t seem to burn really hot so hopefully it didn’t sterilize the soil.”
There is already a fringe of green on the blackened earth.
While fire is a natural part of the sagebrush ecosystem, it can pave the way for invasive grasses and weeds to get established, especially in areas that are disturbed by bulldozers and fire lines. Sagebrush can take several years to grow back after a fire, while cheatgrass, an invasive, fire-loving Eurasian grass that has spread throughout western sagebrush country at an alarming rate in recent years, can start to grow soon after a burn.
“Cheatgrass is always a concern after a fire,” Troyer said. “We know it’s in the seedbank on the Rendezvous. It’s everywhere. Once it’s there it’s really tough to get rid of it.”
Cheatgrass is a cool-season grass, meaning it starts growing in the fall, putting up shoots before the snows, which position it to take off faster than other grasses once the spring melt happens.
Troyer said there is already evidence of cheatgrass and noxious weeds such as white top, diffuse knapweed and Russian knapweed in the Rendezvous burn area. The key, he says, is to try to outcompete the invaders by planting native seeds before they can take over.
Reseeding, and more
WDFW will be using a seed mix specially designed for post-fire rehabilitation in the Methow Valley, which includes a combination of native forbes, perennial bunch grasses, sagebrush and bitterbrush, among others.
“If we can get native seed down to help the existing seed bank, the snow will provide that early moisture and from there we’ll monitor that area anywhere we’ve reseeded and spot treat the noxious weeds we see coming up so they don’t establish,” Troyer said.
“In the aftermath of a fire the future is up for grabs,” said Jeremy Maestas, an ecologist with the Natural Resources Conservation Service. “Herbicides are an essential tool in the toolbox for combatting invasive weeds like cheatgrass. Many invasive species love fire and are well-adapted to out-compete our native plants in that environment. So if we don’t act quick to ensure our native plants come back, we may lose that ground to invasive species.”
With a small burn area, like the Rendezvous Fire, taking a hands-on approach is perhaps more feasible than it is in larger burned areas. However, a growing body of ecologists and land managers are embracing the fact that, in the face of climate change and invasive species, there is a need for some human involvement in post-fire recovery.
“You look at the Methow and we have some of the most pristine intact shrub-steppe left in the West in a lot of areas,” Troyer said. “I’m optimistic it’ll recover. It’ll take some intervention from us, but in the Methow we’re fortunate that we have a massive volunteer base here, with a number of people who will come out and help with re-seeding efforts.”
The WDFW will be looking for volunteers in the coming weeks to help out in the Rendezvous burn area, before the snow comes.