A new study of the 416 Fire burn scar found the fire, which ripped through the San Juan National Forest this summer, did not burn at such a high severity as previously thought.
In July, the U.S. Forest Service’s Burned Area Emergency Response team estimated that about 8 percent of the 54,000-acre fire scar burned at a high intensity.
But a follow-up assessment last week found good news: Only about 3 percent of the fire burned at a high intensity, or about 1,500 acres.
In turn, estimates for low to moderate burns improved. It was originally thought the fire burned about 47 percent at a moderate intensity and about 36 percent at low intensity.
The new report shows the 416 Fire actually burned 30 percent at moderate intensity and 54 percent at low intensity. About 13 percent is considered “unburned.”
The fact that the 416 Fire burned less than thought at a high intensity and more at a low intensity is encouraging for the recovery prospects of the burn scar, said Jonina Vanderbilt, a spokeswoman for the Forest Service’s Columbine Ranger District.
“You just don’t have extensive areas of cooked, scorched land,” she said. “It really is a mosaic burn when you look at the map, and that’s really good news.”
Areas that burn at high intensity take years to show signs of regeneration of vegetation.
While not completely unnatural, high-intensity burns are historically less common and considered to occur more in recent years, in part because of a longstanding practice to suppress wildfires and the drying out of the landscape associated with climate change.
By comparison, about 30 percent of the 70,000 acres burned in the 2002 Missionary Ridge Fire burned at a high intensity.
Speaking at the Animas River Community Forum on Thursday, Lindsey Hansen, a Forest Service invasive and ecology program manager, said areas that burned at low to moderate intensity are already showing signs of new life.
“We know there are pockets that burned really hot and there isn’t anything left,” she said. “But in the majority of (areas) that burned, there are sprouts already coming back up.”
The most recent BAER assessment was submitted to the Forest Service’s regional office in Denver for approval, which should happen next week, Vanderbilt said.
Included in the report is a laundry list of proposed treatment actions the local Forest Service office would like to take to help rehabilitate some of the 416 Fire burn scar. It is up to the regional office to approve what projects will actually occur.
Hansen said the Forest Service would like to control invasive weeds in the burn scar to allow natural vegetation to regrow.
The Forest Service also requested to replant about 100 acres of trees around lower Hermosa Creek Road. And, it would like to replant riparian willows in areas where it makes sense to help stabilize eroding banks.
Hansen said the Forest Service would also like to monitor for an outbreak of the bark beetle. Trees damaged in wildfires are weakened and more susceptible to an outbreak, she said.
As far as recreational trails go, Jed Botsford, recreation staff officer for the Columbine Ranger District, said he was “amazed” that most of the trails in the fire’s burn scar are still intact.
However, risks do exist. On the Jones Creek Trail, about 75 trees were down on a 3-mile stretch, and there is the potential for about 400 more trees to fall, Botsford said.
Gretchen Fitzgerald, a forester for the Columbine Ranger District, also said the trails held up during the fire, but further trail damage could occur after spring runoff.
In the short term, the Forest Service seeks to keep trails closed for safety.
The agency also wants to be on high alert to make sure debris flows do not cause log jams and increase the risk of flooding. Multiple aerial inspections are proposed for the spring.
One major project involves removing the South Fork Bridge, which has fallen into Hermosa Creek, creating a debris dam. Hansen said doing so will require the use of a helicopter.