USA — Even though fire suppression policies and an accumulation of fuels have created an enormous threat of catastrophic fire across the West, most management and fuel reduction treatments still are being conducted with little systematic evaluation of their effects on fire risk in surrounding forests.
A recent study has outlined new methods to do that.
Its just not efficient to do fuel management treatments of our forests without considering the stands nearby, said Claire Montgomery, a professor of forest resources at Oregon State University at Corvallis. Too often we have ignored these surrounding areas and spatial linkages, and we need to start looking at fire risks on a broader level.
The problems are complex, researchers say, and some traditional approaches have been demonstrated as effective, while others now are being called into question. But its increasingly clear that the type of forest or management in one area can affect the risks on nearby areas, and that more sophisticated approaches to this issue would make better use of the money being spent.
One way to reduce loss of timber to fire, of course, is to cut the trees before a major fire burns them and that is whats often done, experts say. However, the equation is often more complex. Young stands that grow after a harvest often burn faster and spread fire more quickly than older, mature forests. So harvesting may increase fire risk to nearby stands, claims OSU.
The study, published in the journal Land Economics, confirms that some traditional approaches to reducing fire risk can work, such as mid-slope treatments that can slow the spread of fire. But its not always true that harvesting stands at younger ages is the most-effective approach to reduce risk. In fact, it may be better to let a timber stand continue to grow if nearby stands are of high value.
Another common strategy is to prioritize stands that are highly flammable for fuel treatment, regardless of location. But it may be possible to reduce fire risk at a lower cost by strategically placing fuel treatments to block fire spread, or by protecting nearby high-value stands.
During recent years, the increasing numbers of land owners at the urban/wildland interface have complicated these issues, because it’s more difficult to get consensus on how land is managed or controlled, according to Montgomery.
Continued advances in what is being called computational sustainability the use of advanced computing systems to run simulations and consider multiple possibilities also may be of some value, she said.
According to this study, there are 12 million acres of dry forest land in Oregon and Washington state alone that are at high risk of fire, usually due to accumulation of small trees, bushes, debris and other undergrowth resulting from fire suppression efforts during the past century.
Mechanical thinning, prescribed fire and other approaches often are useful in reducing the risk of catastrophic fire, but budgets to accomplish this are often hugely inadequate. This increases the need to maximize the cost-effectiveness of whatever fire reduction efforts are attempted, the researchers said.
The study suggests that this work should provide a framework for issues including further research on fire risk management issues such as salvage logging, effectiveness of various fuel treatments, the tradeoffs between fuel treatment costs and fire suppression costs, and non-timber values.