Del Mar, Calif., is known for its beautiful beaches and appealing downtown, yet inland are dry stretches of scenic canyons dotted with multimillion dollar hillside homes. The canyons are as picturesque as are the homes; the problem is that the canyons are a fire hazard headache for the Del Mar Fire Department.
The department determined that if a forest fire fueled by a hot, dry Santa Ana wind struck the Del Mar canyons, it could torch certain areas in a matter of minutes, especially since the canyons have narrow roads that can hamper firefighters in reaching fires quickly. And with homes interspersed throughout the hills, evacuation from a severe forest fire would be difficult and dangerous.
That's why the Del Mar Fire Department turned to urban foresters to beef up its firefighting repertoire. Urban foresters use software and fieldwork to identify high-risk areas with overgrown vegetation or narrow buffer zones, and develop plans for reducing these fire hazards, giving firefighters additional time and buffer zones to combat fires.
Understanding All Components
One of the significant fire hazard areas identified by the Del Mar Fire Department was the Crest Canyon area. The department determined that more than 60 homes could burn in less than 15 minutes if a large fire swept through the area -- quicker than it would take firefighters to reach the houses along the narrow dirt roads.
"In Crest Canyon, with houses intermixed with heavy vegetation, there is a really significant fire hazard, especially because there are very narrow roads so it causes more issues for firefighters," said David Ott, Del Mar and Solana Beach fire chief. "There is the possibility for a fire to want to continue to burn through the entire area."
To mitigate the high risk of a disastrous fire, Ott looked for help from Dudek, an engineering and environmental consulting corporation that helps solve regulatory issues for municipal agencies and major landowners. With a $140,000 grant from the Federal Emergency Management Agency, Ott hired Dudek's urban foresters to help reduce fire hazard in the Del Mar canyons.
Like standard foresters, urban foresters work for government and private industries to manage and protect forests in urban environments ranging from cities to the rural landscapes often just a couple miles from suburbia. Part arborist, forest planner and fire prevention expert, urban foresters have to understand all components of an urban forest, including knowledge of plants and their ecosystems, soil, water and wildlife, as well as knowing the dynamics of forest fires and fire prevention.
Dudek's urban foresters set out to the hills of Del Mar with GIS and recorded the types of vegetation, the density, weight and volumes of dried brush -- or "fire fuel" -- the topography of the areas including the direction of landscapes in relation to the sun, temperatures and weather.
All the information was compiled into field assessments and fire behavior modeling maps with BehavePlus and FlamMap software. Using complex algorithms and logarithms, the software created fire-modeling maps that predict fire behavior characteristics in the event of a wildfire, including the rate a fire would spread and flame height. The programs factor in potential conditions such as the moisture in fire fuel and wind speeds.
The result is a vegetation management plan for Del Mar that targets specific areas for brush removal to mitigate fire exposure. Unlike Del Mar's previous broad prevention efforts, the new vegetation management plan used the field assessment maps to identify precisely where the fire department needed to reduce hazardous fuel volume to limit fire continuity, lower potential threats to property and provide buffer zones so firefighters can more effectively control the spread of fire.
"We developed a plan of interlacing the landscape with islands of fire fuel and learned how we could take out parts of fuel so the fire won't burn as rapidly," Ott said. "With islands, a fire can't carry as well since there is no continuous fuel and the fire slows down significantly so we can get there."
The Del Mar fire crews went deep into the canyons with saws and removed dead and dying plants, as well as dead material accumulated on some plants. They cut horizontal and vertical rows of plants and brush, and created "islands," keeping a distance of about 9 feet between plant groupings, which slows the spread of flames in a landscape.
They also separated the "canopy layer" -- the interconnected foliage of uppermost tree branches -- from ground vegetation, by reducing the height of lower-level plants and cutting low limbs from trees. This prevents what firefighters call a "fire ladder" where flames can move from the ground and ignite trees.
When these tasks were completed, fire crews had created not only vegetation islands that would impede a fire, but buffer zones and defensible space that would let firefighters evacuate homes and fight fires more effectively. Yet brush wasn't entirely decimated. The crews were sensitive to the landscape, identifying the needs for soil stability, wildlife habitat, aesthetics and resident privacy.
"The goal is not to go in and clear-cut and take everything out," said Michael Huff, manager of urban and community forestry and wildfire prevention planning at Dudek. "It's not desirable for homeowners, and you have soil erosion issues. The goal is to, No. 1, reduce the amount of fuel in a given area; and two, break up the continuity of fuel, since a fire will only move through an area with continuous fuel."
Dudek's mapping of fire hazards helps fire departments predict how a forest fire will behave and prepares fire crews to fight the blaze, Huff said.
Also, the fire hazard maps assist in communications with city officials, and can help a fire department secure a grant and/or city funds, since the maps reveal precise danger areas and what would happen to those areas in the event of a fire. And when homeowners living near fire hazard areas are shown the maps, they are often willing to cooperate with a fire department's advice.
"We can show a map that reveals how huge a fire can get near residential homes, and the homeowner usually becomes concerned and is a lot more willing to have the fire department come in with full on cooperation," Huff said. "We can show how it is now, and we can actually tweak the model to represent an area that has been treated."
Fire prevention is not a new science, but by utilizing urban foresters' latest technology and expertise, Ott strategically maximized fire prevention -- a very important role for a firefighter.
"We used the latest technology to affect our fire prevention plan and looked at the big picture to hopefully maximize what we can do instead of looking at a fairly narrow perspective," Ott said. "The real effect is fire prevention, is where the community will receive the most significant benefits."
Combining the use of high-technology software with fire prevention has caught on, said Ott, who has been contacted by other communities interested in his program. Dudek's urban forestry and fire prevention division has about a dozen clients, said Huff, but Del Mar is a growing area for the company.
Ott is pleased with the fire prevention results, but the work is not done. He wants to see more investments in fire prevention in the coming years, so that homeowners and fire crews consistently clear out fire fuel.
"It's great that we've done this," Ott said, "however, vegetation grows back, and it's the responsibility of property owners as well as the fire district to maintain the vegetation management plan."