By Ann McCreary
Because they are adapted to fire, the forest and shrub-steppe lands burned in the Carlton Complex Fire can be expected to recover, although many areas of the Methow Valley landscape will remain changed for the rest of our lifetimes.
“Our regular haunts are changed,” said Susan Prichard, a fire ecologist who spoke as part of a lecture series about the Carlton Complex Fire sponsored by the Methow Conservancy.
“Even for a fire ecologist I was blown away by this event and am still kind of scratching my head about it,” said Prichard, who conducts research on fire ecology at the University of Washington.
Prichard and Connie Mehmel, a U.S. Forest Service entomologist, spoke Monday (Feb. 2) at the Twisp River Pub about the fire’s impacts on the valley ecosystem, and post-fire recovery.
Because of the intensity of this wildfire, even some forested areas that had been thinned or treated with prescribed burning were fully consumed in the Carlton Complex. That raises questions that will be explored by forest managers and scientists, Prichard said.
“There’s a type of fire that’s too extreme. We need to do a lot of research on this,” she said.
While many trees were destroyed in the fire, many others sustained partial damage. The next three years will tell whether or not those trees survive, said Mehmel.
Most trees that are too damaged to survive will die within a year of the fire, but some will continue living for up to three years, Mehmel said. Forest managers will be assessing survival in the next three years, she said.
Trees injured by fire become targets for another threat to their survival — an influx of insects that attack fire-damaged trees. Bark beetles and wood-boring insects can detect fires from great distances and arrive in the wake of wildfire to lay eggs in the burned trees, which then become food for the next generation of insects.
Within days or weeks of a fire the insect damage begins, Mehmel said. If the fire occurs outside the period when the insects are “flying,” damaged trees may become targets the next season.
Fir beetles next?
The Douglas fir beetle, for instance, is active from early May through mid-July, so wasn’t a threat after the Carlton Complex Fire in July, but will likely be a concern this year.
“There will be damaged trees that may be attractive to Douglas fir beetles next spring, especially in the South Summit area [at Loup Loup Pass],” Mehmel predicted.
Dwarf mistletoe is another threat to tree survival, Mehmel said. A parasite, the mistletoe weakens the tree, making it more vulnerable to injuries sustained in fire. Because it hangs from branches toward the ground, mistletoe can also provide a fuel ladder that carries fire to the crown of the tree.
Douglas fir is more susceptible than ponderosa pine to damage from mistletoe and insects, therefore the post-fire recovery of forests is likely to produce healthier tree stands with fewer surviving Douglas fir and more pines, Mehmel said.
Any discussion of ecosystem recovery after wildfire should consider potential impacts of a changing climate, Prichard said. Extreme fire events like the Carlton Complex Fire are predicted to become more frequent due to more drought and extended wildfire seasons.
Some burned areas may be susceptible to burning again, which can set back recovery for many years, or transform forest landscapes to grasslands, Prichard said.
Research has shown that landscapes with a mosaic of components, including burned patches next to older tree stands, are healthier and more resilient. A decades-long policy of fire suppression, however, has changed the historical pattern of frequent but smaller and less intense fires, which create a varied landscape and support fire-resistant species like ponderosa pine, Prichard said.
“In the absence of fire, forests are succeeding to Douglas fir. With multiple light surface fires we would get more ponderosa pine,” Prichard said.
“One of our best tools is fire” to help create healthy landscapes, Prichard said.
“This time after the Carlton Complex gives us time to contemplate what we’re going to do. On Forest Service lands, state lands and private property we need to become more fire-adapted,” Prichard said.
