Many of the watersheds in the western United States are situated in high wildfire hazard environments. These areas possess the ingredients necessary to support large, intense, and uncontrollable wildfires. When this type of wildfire occurs, the result can be deterioration of watershed function, damage to wildlife habitat, destruction of property, and loss of human life.
There are three factors which influence wildfire behavior - weather, topography, and fuels. If the goal is to reduce wildfire intensity and improve our ability to control a fire, one of these three factors must be modified. Unfortunately, there is little that can be done to change the weather or topography. Consequently, our opportunities to reduce the wildfire threat lie in the modification of fuels.
In the case of wildfire, fuel is typically synonymous with vegetation. Through appropriate manipulation of vegetation, a wildfire can be made to burn slower, cooler, for less time, and with shorter flames - in a word, with less severity. This can be accomplished by reducing the amount,decreasing the height, altering the arrangement, and increasing the moisture content of vegetation available for burning.
There are a variety of techniques or tools available to land managers to accomplish appropriate vegetation management for wildfire threat reduction. Most of these fall into the following categories.
Mechanical: These approaches utilize hand tools and drawn implements to cut, mow, chip, grind, disc, and plow vegetation. Besides reducing overall fuel loading, mechanical treatment can break up vertical continuity of 'ladder fuels' (layers of live and dead vegetation, especially with low-growing limbs) which carry flames from a ground fire to a more destructive canopy fire.
Burning: Prescribed fire is the intentional and controlled use of fire to modify fuels. Often, the finer fuels (less than 2" in diameter, for example) are targeted since they spread more rapidly. Larger fuels may be consumed to break up horizontal continuity of the fuelbed.
Livestock grazing: depending upon the type of vegetation, season, topography, and other factors, domestic livestock can be used to consume fuels.
Greenstripping: the replacement of hazardous vegetation with less flammable plant materials is another option.
None of these techniques is a panaceaŠ each has advantages and disadvantages. The appropriateness of a technique for any given site will vary by vegetation type, scale of treatment (e.g., around a home, a community fuelbreak, or landscape level), cost, potential for weed establishment, public receptivity, and other factors.
In summary, the western U.S. will continue to experience intense and uncontrollable wildfires. We have two choices: either we resign ourselves to live with the consequences of high intensity wildfires, or we become actively involved in the management of fuels. -
You can reach Ed at 775-782-9960/esmith@agnt1.ag.unr.edu
