USA — The large wildfires becoming more frequent in the West are a product of conventional fire management policies, said Mark Finney, Ph.D., a research forester with the U.S. Forest Service Fire Lab in Missoula.
Its a consequence of our exclusion of fire for the last 100 or more years, he said from his office in Missoula. Weve been so effective at removing fire, were now seeing fires burning to the worst case and getting very large fires. If we accept that premise, then we have to manage and introduce fire under our prescription that doesnt consume all the fuel on site.
Finney presented his research on fire behavior in landscapes of varying levels of logging and prescribed burning at last weeks Fire on the Landscape lecture series in Helena. While logging or thinning is often touted as a means to mitigate fire, he has found it does little to stop a wildfire. Only prescribed fire, set under more moderate conditions, has been proven to impact large fires burning under extreme conditions.
Theres a confusion that if you do timber management youre doing fuel management — youre not, Finney said. Were not going to cut our way out of the problem, but there are ways to do this strategically, get the benefits and have a sustainable fire management approach.
Finney found that fire ripped through logged areas, and only units where prescribed fire was introduced showed effectiveness in stopping or mitigating wildfire spread.
This isnt saying that timber harvesting is bad or good, its just that it doesnt substitute for the change in fuel structure under prescribed burning, he said.
Fire breaks are another conventional mitigation tool that have proven ineffective, Finney said. Spotting easily breaches fuel breaks, potentially leaving firefighters in danger, he said.
While there is no magic number on how much prescribed fire it takes to impact a large wildfires behavior, the few hundred acres often burned did not have an impact on large fires. He did start to see effects in the 20-40 percent range, however.
Conditions may not be good for prescribed fire as dry weather begins to dominate the summer months, but once wildfires start, officials may wish they had taken the opportunity to do more prescribed burns, Finney said.
Although the benefits of prescribed fire are known, some say it is not used nearly enough, partly because of the fear of a prescribed fire burning out of control. While escaped fires grab headlines and give people someone to blame, there will never be an escaped prescribed burn that equates to the damage caused by the wildfire it is designed to stop, Finney said.
Prescribed fires are never set under the same conditions as wildfires. Theres a huge amount of technique, so really the risks are far less, he said. Its not risk-free, but by doing nothing youre ignoring the potential. Which risk would we prefer?