Ashland controlled fire burns too hot, kills legacy trees
A reddish patch of forestland high above Ashland is a scarlet example that, when it comes to burning, foresters still have some learning to do.
The 65-acre patch intentionally set off June 6 as part of the Ashland Forest Resiliency Stewardship Project burned hotter than intended, resulting in scorched portions of the forest canopy and an unknown number of dead or dying trees that the controlled burn was supposed to enhance, authorities said.
Those dead trees include some large "legacy trees" whose progress has been under study here in the Rogue River-Siskiyou National Forest near Horn Gap, in an area visible to hikers and mountain bikers on Forest Service Road 400 along the No-Candies Trail — and even to motorists on Interstate 5.
"We got more scorched trees than we wanted," said Don Boucher, Ashland Forest Resiliency Stewardship Project manager. "Some will live. Some will die."
The scorched area represents about one-fourth of the nearly 250 acres burned this spring as part of the AFR project, which used fire, logging and commercial brush-thinning to improve nearly 7,600 acres of the Ashland watershed while reducing wildfire threats.
The controlled burn in the scorched unit did not damage the forest duff nor soils, did not jump its boundaries, and no one was hurt on the ground, said Darren Borgias of The Nature Conservancy, which joins the Forest Service, the city of Ashland and Lomakasti Restoration Project as AFR partners.
Borgias said the burn represents "a fantastic opportunity" to learn more about controlled fire management, and AFR plans to monitor the area and use aerial photographs to assess the losses and follow its recovery.
"We'll actually know how much of the canopy is impacted, and we'll also look at those legacy trees," said Borgias, whose TNC heads up AFR monitoring. "We want to look at this on a landscape perspective. It really is, though, a small footprint."
As part of its mea culpa, AFR leaders plan public tours later this month to show and describe what happened that day for those who wish to see it for themselves.
"There's no intent among the partners to pretend it didn't happen," forest spokeswoman Chamise Kramer said.
As for exactly what happened that day, no one yet knows for sure.
Fuel moisture levels as well as weather and wind conditions were well within the normal burn parameters for successful controlled burns, Borgias said.
Two sets of contract crews June 6 used drip torches to ignite brush and downed woody material as they worked their way from one edge toward the center, then burned their way back at a 90-degree angle.
The fire burned normally but it began to generate more heat than expected, and by the end the intensifying heat singed needles far up Ponderosa pines and other large trees, including some of the canopy, Borgias said.
"It's not torched," Borgias said. "It's scorched."
Boucher said foresters are looking at a combination of factors, including the amount of downed material left to burn, whether more pre-burning of piles would have helped reduce the intensity, and whether slope and aspect of the mountainside played roles.
Another possibility is that the relatively dense forest canopy allowed less heat to escape than expected, generating a more intense burn that triggered the scorching.
"It's a plausible explanation," Boucher said. "We could have very well trapped the heat."
The lessons learned perhaps will translate into more but expensive pre-treatment to lessen the amount of downed material to burn, as well as changes to the ignition patterns of future controlled burns in stands like these to learn when hot becomes too hot.
"We still have to know how to recognize that threshold," Borgias said.
In the future, the June 6 burn will have accomplished much of what it sought to do — create an open forest canopy along this slope that looked like it did a century ago, AFR members said. It just did more than intended as foresters continue to learn the nuances of introducing fire to the forest.
"We've inherited 100-plus years of fire exclusion," Lomakatsi Executive Director Marko Bey said. "We're trying to turn that biological clock back.
"The goal is to kill some trees, not the overstory," Bey said. "Humility's always a good thing."
— Reach Mail Tribune reporter Mark Freeman at 541-776-4470 or email@example.com. Follow him on Twitter at www.twitter.com/MTwriterFreeman.