Thursday, January 29, 2009
Wildfires and Dead Trees Needed
This is a letter to the Register Guard in Eugene, Oregon responding to a recent letter from Mike Dubrasich, a timber industry advocate.
WILDFIRES AND DEAD TREES NEEDED
In his January 19th Register Guard guest editorial on forests and fire, Mike Dubrasich, suggests that fire suppression had led to higher fuel loadings, and hence is responsible for the large blazes we have seen around the West in recent years. And he advocates logging as a prescription to "restore" forests to their historic condition. Unfortunately Mr. Dubrasich conflates very different fire regimes into one narrative that inaccurately portrays the causes of recent large blazes as well as the influence that fire suppression may have had on PNW forests.
Only the lowest elevation grasslands, oak savannas and ponderosa pine forests tended to burn frequently and contrary to timber industry rhetoric even these forest occasionally burned in stand replacement fires. Fire suppression may have increased fuels in these forests, but since only a small proportion of our woodlands are of this forest type, the influence of fire suppression is greatly exaggerated.
The bulk of all forest types in the PNW, including most fir, hemlock, spruce, and other mid-higher elevation forests historically burned infrequently and as mixed or high severity stands replacement fires. Because of the naturally long interval between fires--often hundreds of years--fire suppression has had a minimum affect on most forests types since they have not "missed" a fire rotation and there is no unusual fuel buildup.
This is important because the majority of acreage burned annually occurs in higher elevation, longer fire regime kinds of forest types. Large blazes in these forest types cannot be attributed to fire suppression activities, nor are large stand replacement fires "abnormal" or a sign of "unhealthy" forests as timber industry advocates try to portray.
The main factor contributing to large blazes around the West is not fuels, but climatic/weather conditions. The period between the 1940s and 1980s was moister and cooler than previous decades earlier in the century as well as recent decades. This is exactly the same time that people are suggesting fire suppression was effective. But another interpretation is that it was too wet to burn well during that period.
Timber industry proponents try to link fuels with fire, but it is climatic and weather conditions that permit any fuels to burn. If you have extensive drought, coupled with low humidity, high winds, and high temperatures, you can get large blazes—no matter how much or how little fuel you have.The West has been experiencing some of the worst droughts in centuries so it's not surprising that we are seeing large blazes.
The 2002 Biscuit Fire illustrates this finding. Old growth stands and north slopes—the very forest types with the highest fuel loadings and greatest biomass--were the least likely to burn. By contrast younger forests, open savannas of Jeffrey pine and shrub dominated south slopes which had far lower fuel accumulations made up the bulk of acreage charred by the blaze.
Another study found that areas that had been "salvage logged" after the Silver Fire and subsequently reburned in the Biscuit Fire had higher fire severity than unlogged stands, even though these stands obviously had far less biomass (fuel) than unlogged stands.
The explanation is simple—north slopes and old growth forests retained moisture better--and despite the high fuel loads, are more difficult to burn. By contrast, open forests and south slopes exposed to the sun dry out sooner and typically had more "fine" fuels, thus burn better. This is one reason why "thinning" can enhance the chances that a stand will burn because removing trees opens up the forest to higher solar radiation and wind—both of which contribute to fire spread.
A third misconception perpetuated by the timber industry is the idea that dead trees are somehow undesirable and an indicator of "unhealthy" forests. In reality dead trees are the foundation for forest soil productivity. Dead trees are also important for most forest dwelling species—with fully 2/3 of all forest species dependent upon them at some point in their lives. Wildfires, along with insects, are the major agents for producing dead trees and contributors to healthy forests.
Contrary to popular opinion, our managed forests are the ones that are "unhealthy" and "sick". Managed forests typically have less dead trees, and are biologically impoverished and degraded.
The timber industry keeps trying to tell us that all they care about fixing the forests degraded by none other than past forestry practices—and now suggest that we need more logging to fix the problems they created. I am willing to bet if there were no profit in logging our forests, they wouldn't give a hoot about forest health, restoration, wildfires or anything else. It's all a rationalization for exploitation.
Forests have survived for thousands of years with wildfire and insects and they don't need our help to survive or be healthy. I suspect forests live in far more fear of foresters who possess too much hubris, than of any wildfire.