SUMMIT COUNTY " An experimental fire planned for beetle-killed lodgepole pines in Rocky Mountain National Park should help determine when the trees are most flammable.
Officials incessantly cite the increased risk of fire danger in beetle-killed forests as the prime reason to cut and thin dead lodgepole pines.
But controlled burns also could prove a useful tool in treating blighted stands of pines, especially when it comes to regenerating new stands.
The risk of a crown fire is thought to be greatest in stands comprised primarily of standing dead trees with red needles than among healthy, green trees.
But the flammability may drop once the needles fall off the trees. Forest researchers say there is still some debate about exactly when the trees are most flammable and whether the potential for devastating crown fires changes as the red needles fall to the ground.
Sometime in the next few weeks, they hope to start answering some of those questions by deliberately torching both beetle-killed trees at various stages of mortality, as well as live lodgepoles, in Rocky Mountain National Park.
The experiment is aimed at learning more about the impacts of the mountain pine-beetle epidemic on fire behavior, according to Monique Rocca, assistant professor of fire science at Colorado State University.
"Our hypothesis is that green trees will burn moderately," Rocca said. "Dead trees with a full canopy of red needles will burn more intensely, but the flammability drops back down when the needles fall off."
Basically, the team of forest ecologists will ignite individual lodgepoles with a drip torch to see how long it takes for the trees to burn up entirely, and comparing the burn rates for different trees.
The research could also help determine how important fire is to the regeneration of lodgepole-pine forests, and whether burning trees with snow on the ground is a viable alternative to logging in the quest to protect communities from wildfires.
Along with investigating the flammability of lodgepole-pine crowns, the pilot project also will look at the mechanisms of pine-seed dispersal following beetle attack and the survival of beetle larvae following burning.
"We're also interested to see if the cones will open in a winter burn," Rocca said. "It would be nice to know if we can generate a new cohort of trees by just burning the crowns, or whether the forest floor also has to be burned," she said. "We may find it important to use fires to create the next generation of lodgepole pines."
Some lodgepole pinecones open only with the intense heat of a fire. Other cones simply open some time after falling to the ground. Rocca said those differences are determined by genetics and evolution.
Research from Yellowstone suggests that lodgepoles at lower elevations, where fire is more frequent, produce a higher number of the fire-dependent, seratinous cones, while pines at higher elevations, where there is less fire, produce more of the non-seratinous cones.
Colorado research is limited, but there are indications that there is a good mix of both types in many of the state's lodgepole pine forests, Rocca said.
The Rocky Mountain National Park experiment, scheduled to occur in the next few weeks after a snowfall, could also help determine whether it's technically feasible to introduce fire as a tool for forest regeneration.
The prescribed burn will be ignited after a snow or sufficient wetting rain. This prescribed burn unit is located in Horseshoe Valley, south of Fall River and north of Deer Ridge Junction.
Safety factors, weather conditions, air quality and environmental regulations are continually monitored as a part of any controlled burn. For more information, contact the park information office at (970) 586-1206.
Bob Berwyn can be reached at (970) 331-5996, or at firstname.lastname@example.org.