PINEWOOD LAKE — A federal forester flicked a Bic, igniting a first bone-dry pile of culled young pines — testing conditions for the looming task of torching 180,000 similar piles across Colorado.
The continued construction of houses in burn zones is forcing this effort to thin overly dense forests and reduce the risk of super-intense wildfires.
For years, federal forest managers have targeted young trees in areas near homes to try to prevent the sort of devastating wildfires that exploded across thousands of acres in Colorado last year, killing six people and destroying hundreds of homes.
Ecologists question the strategy of manually thinning by targeting young trees, warning that this could kill the capacity of forests to regenerate.
But the most immediate challenge for fuel technicians Matt Champa and Joe Parr, and their counterparts statewide, is getting the already-cut piles burned.
As flames licked upward amid mature ponderosa pines towering above high-value horse farms and homes, Champa had to quickly make an assessment.
"Conditions just aren't favorable. We need more snow. We need a minimum of 3 inches," he said, deciding to postpone burning of 900 more piles 8 miles west of Loveland in the Arapaho and Roosevelt National Forests. "This thing could burn through the night, the wind might get it, and it could creep out."
Pile fires simmering and spreading could create more work than these two could handle. State health-department regulations on particulate air pollution further complicate the burning, limiting the number of piles foresters can torch.
All-out prescribed fires that burn dense forests while trees are still standing — a more cost-efficient method of thinning — are even more difficult to get done because safety protocols require dozens of firefighters with heavy equipment to surround and monitor flames.
The upshot is that federal foresters
The Forest Service will be lucky to burn 30 percent of the piles this winter, given the light snow so far, said federal fire ecologist Brenda Wilmore, who oversees regional tree-thinning efforts.
Wilmore defended the approach of targeting young trees.
"The forests are overgrown, especially in Front Range areas. We have a lot of new trees coming up. Those young trees, if we leave them, they provide a ladder," she said. "Wildfires will climb up that understory ladder into the mature trees as well.
"If we don't do anything, the ecosystem is actually changing to different and more flammable species" such as white firs, she said.
However, killing young trees is controversial. The bark-beetle epidemic over the past decade has ravaged more than 3 million acres of forest in northwestern Colorado, mostly west of the Continental Divide. An emerging push to restore the health of these forests has emphasized the nurturing of young pines of diverse species so that dying forests will regenerate.
Removing and burning young trees may make sense where volatile fuels have built up near homes "but certainly not on a large scale," said Bill Bowman, director of the University of Colorado's Mountain Research Station west of Boulder.
"It makes absolutely no sense to go around thinning all your young trees because you are killing age classes that are potentially going to replace the large trees after there is a disturbance, like pine beetles," Bowman said. "The regenerative capacity of that forest is compromised by removing the younger trees."
West of the Continental Divide, up to 90 percent of trees in some areas are dead or dying. But here along the Front Range, about 40 percent or less are afflicted.
The thinning has let in more sunlight, and a few ponderosa seedlings are sprouting. As they tended to the test burn, Champa and Parr counted six and figured it would take them about five years to reach a height where they might survive — if they receive enough water.
They turned to "chunking" their test fire — stomping across the charred logs, sweeping in small branches and needles around the fire.
State air-quality officials have asked the federal foresters dealing with burn piles to do this.
"In theory, chunking it means this is going to burn down to nothing a lot quicker, and the fire will put out a lot less smoke," Champa said.
But chunking each burn pile — some as deep as 8 feet — reduces the number a crew could torch in a day to about 50. They had planned to burn 75 piles a day.
"It would be a lot better if we would burn 900 piles," Champa said. "We're going to be at this all winter."