USA — As wildfires put more and more human lives and property at risk,people are looking to fire managers for protection.
Typically, fuel is the sole consideration used to decide the location of sitetreatments – where trees and shrubs are cleared away or burned in order tominimize the risk of a future fire. However, people also strongly affectwildfires.
This influence is not well understood, and is often overlooked when makingmanagement decisions.
To help fire managers identify the best locations for site treatments in oneparticularly fire-prone region in Southern California, a University ofWisconsin-Madison team developed a map that incorporates both environmental andhuman factors to pinpoint where the most devastating wildfires are likely tostart in the Santa Monica Mountains, located just north of Los Angeles.
“The vegetation in Southern California is extremely flammable. In someplaces, it’s like there is a continuous blanket of fuel on the ground,”says Alexandra Syphard, a postdoctoral researcher in the UW-Madison departmentof forest ecology and management, who will give the talk. She notes that thisfuel is easy tinder for cigarette butts, campfires run amok and the intentionalflames of arsonists. Through these and other means, humans cause 95 percent offires in southern California.
Most of these fires occur near the wildland-urban interface, where houses andother structures commingle with forests and other wild vegetation. “Thewildland-urban interface is where houses are most vulnerable to fire becausethey are intermingled with fuel. The problem is that this is also where humansare most likely to start fires,” says Syphard.
To generate her computer models, Syphard utilized a variety of datadescribing the Santa Monica Mountain region, including information about fireignitions and the area burned by fires, the locations of human-built structures,roads, trails and the wildland-urban interface, as well as data about the localclimate and terrain. Syphard collaborated with the U.S. Forest Service’sNorthern Research Station in Evanston, Ill., to create the computer models.
“We found that, in terms of fire ignitions, the vast majority of firesare starting near human infrastructure or along roads in the wildland-urbaninterface. But, ultimately, the area burned by a fire is more a function ofother biophysical variables such as the type of terrain, climate or vegetation,”says Syphard.
By combining data about where fire ignitions are likely to occur withinformation about where fires are most likely to spread, Syphard identified andmapped places where the most destructive fires are likely to start in the SantaMonica Mountains. These spots are obvious targets for site interventions thatwill save structures and lives, while maximizing the limited resourcesdesignated for this purpose.
“The underlying issue here is that as we add more houses to thewildland-urban interface, we will get more fires,” says Volker Radeloff,associate professor of forestry at the UW-Madison, who oversees the laboratorywhere Syphard works. “Alex’s work shows us that at some point we’ll have tomake tough land use planning decisions in order to control wildfires.”
“We need actions at all levels-by individual landowners, communities andat the federal level,” says Radeloff. “We need federal policies that,at the very least, do not foster sprawl in the wildland-urban interface.”