Defensible space: Wildfire experts say planning, preparation can reduce the risk of losing homes 

One easy tip? Regular landscaping around your home could save it during fire season

By: - July 29, 2021 4:32 am

Avimor, a growing development in the foothills outside of Boise, was one of the first Firewise Communities in Idaho. Photo courtesy of Avimor Development.

Brett Van Paepeghem doesn’t mince words when he talks about the potential consequences of this fire season.

“It’s frightening,” Van Paepeghem said in a telephone interview. “The drought, the heat, the forecasts; all of it is kind of a recipe for disaster. It’s scary. We’re sitting in, potentially, one of the worst fire seasons I have ever seen in my life.”

Van Paepeghem is the south Idaho project manager for Idaho Firewise, a nonprofit organization that coordinates and promotes wildland fire education with the goal of reducing loss due to fire. 

He’s concerned about drought and climate conditions crashing up against more recent building trends. 

Over the last 10 years, Idaho was the second fastest growing state in the country, based on percentage growth, according to the U.S. Census Bureau. 

Much of the West also experienced rapid growth. 

“Where are we growing?” Van Paepeghem asked, rhetorically. “Into our wildland urban interface. That seems to be the typical direction. That’s where we’ve got room for new people and subdivisions and buildings, in our wildland urban interface.”

Fire experts define wildland urban interface (they often use the acronym WUI) as the area where human development and structures meet or mix with a natural environment and wildland fuels. 

And as such, wildland urban interface areas are at a higher risk for wildfire damage and loss. 

The city of Boise has a map showing the areas designated as wildland urban interface. Multiple communities in Idaho and across the West have also adopted wildland urban interface codes for development.

What can homeowners do to prevent loss during wildfire season?

Fire experts told the Idaho Capital Sun there are several things homeowners and builders can do to reduce the risk of fire damage, including building homes and roofs with fire resistant materials, clearing gutters of leaves and debris, using rock gravel over bark mulch for landscaping and maintaining a protective defensible space in the areas closest to structures.

“It’s human nature to think bad things will only happen to somebody else,” Van Paepeghem said. “I think we are all guilty of this on many levels other than wildfire.”

That’s not to say there aren’t things — including simple things — humans can do to prevent wildfires and reduce the risk in the event of fire. 


Pat Durland, a consultant with Stone Creek Fire who began his career on a hotshot fire crew and spent 30 years managing wildland fire programs, says many losses due to fire can be prevented or reduced if humans understand the risk factors and take steps to address the risk.

“This is a solvable problem, and more people need to understand they need to be doing something. They need to be proactive rather than reactive,” Durland said. “We can make this problem go away. When it comes to natural perils, this is an easy one and we can fix this. There will be other problems for future generations, and it would be great to take this off the list.”


“It starts with yard work”

Brett Van Paepeghem, southern Idaho project manager for Idaho Firewise, prunes plants and removes dead flowers from the Idaho Firewise Demonstration Garden at Idaho Botanical Garden. Photo by Clark Corbin/Idaho Capital Sun.

Van Paepeghem and Durland spend most of their time helping Idaho residents, homebuyers, developers and homebuilders reduce the risk of loss due to fire. 

They believe in taking preventative steps to reduce the risk of loss due to fire and both advocate leaving your home if it is threatened by a fire, rather than staying to fight and defend it. 

Some of the steps are as easy as keeping up with yard work. 

“​​The research has shown us that the probability of your structure resisting an ignition from an external source of fire is largely dependent on your structure and how it was built and how it is maintained and the 100 feet around it,” Durland said, recommending the wildfire tips available on the website 

“You need to worry about whether your roof is made of noncombustible materials, whether your gutter is full of leaves and how close you are to fuels that will rapidly burn,” Durland added. “The zero-to-five feet area (around your home) is really critical.”

Durland advises people to avoid bark mulch and Juniper trees around their homes, because they can fuel a fire. They should keep landscaping spaced out and trimmed up, removing dead material that would help a fire spread.


Van Paepeghem tends to the Idaho Firewise Demonstration Garden at the Idaho Botanical Garden in Boise to offer people ideas for safer landscaping materials that are still practical and visually appealing. 

He urges people to to focus on less density, keeping lawns moved and brushes pruned and using drought resistant vegetation to cut down on risk and fuels. 

“All plants are not created equal; some burn a lot more readily than others,” he said. “We suggest not using coniferous plants within 30 feet (of structures) and use lower-growing, higher-moisture content plants instead.”

What do you mean by defensible space? 

Van Paepeghem stresses the importance of looking at your property in terms of three zones extending out from the house. 

The first area, zone one, is the area immediately around the house, out to about five feet. That’s the most critical area to keep clear of landscaping fuels. 

Zone two stretches from five feet out to about 30 feet. Here, Van Paepegan stresses the importance of leaving space between plantings so landscaping doesn’t become one continuous line of solid fuel.

Zone three stretches out from 30 feet away to 100 feet from the home. Here Van Paepeghem still stresses clearing out and leaving space between plants, shrubs and trees. He urges people to remove ladder fuels, which are grasses or shrubs growing under trees that can take fires off the ground and into the tree canopies. 

One note of caution Van Paepeghem adds is that fire can travel much more quickly on steep slopes. He urges people to extend the zones out if the property is on steep sloping land. 

However, many new building trends don’t align with the three zones Van Paepeghem discusses because houses are often built so densely and so close to each other that zone two could include the neighbor’s house and zone three could take in multiple rooftops in a subdivision. That’s another factor that worries Van Paepeghem. 

“They are cramming a lot of homes into tiny spaces, and this is just counterintuitive to be able to create survivable space, or defensible space using the zones around a home,” Van Paepeghem said. “That property is so small that next door neighbor is only 10 feet away. When you’ve got a situation like that, I don’t care how you landscape, that is a risk in itself. The homes themselves become the fuel for the fire.”

What is a Firewise Community and what can builders do?

From the outset, Ada County’s Avimor development was planned and constructed as a Firewise Community to meet national benchmarks from the program that is administered by the National Fire Protection Association, Avimor managing partner Dan Richter said in a telephone interview. 

This file photo shows beginning stages of development of Avimor, a Firewise Community being built in the foothills north of Eagle and outside of Boise. Photo courtesy of Avimor Development.

The heart of the program is getting homeowners and the entire community involved to reduce wildfire risk to homes and the community. 

Other Firewise Communities in Idaho include Wilderness Ranch, Hidden Springs, Harris Ranch North and Warm Springs Mesa in Boise, Armstrong Park in Coeur d’Alene, Conkling Park in Worley, Heatherlands HOA in Hailey, the city of McCall, Wapiti Creek Summer Homes in Lowman and Mackay Fire District in Mackay, among others, according to Idaho Firewise. 

In Avimor, that means using cement siding instead of wood siding, using fire resistant materials in roofs, having a landscaping plan and using rock mulch around homes.

Avimor has a conservation director, and every five years that person reviews homes to make sure there haven’t been modifications and that landscaping is trimmed and maintained. 

Avimor developers also purchased a mower to trim the foothill slopes that come up to the community and to mow along the Idaho Highway 55 right of way around the community. 

“We know that all of these places burn eventually, and we’ve just got to make sure when we do experience fire that we can keep our community safe,” Richter said. “We’ve put in ponds around our community so if we do get fire, helicopters can use them to dip out of. We keep our irrigation tanks full as well.”

Avimor is a nearly 23,000-acre development located north of Eagle in the foothills outside of Boise. Construction began in 2004. When it’s complete, developers envision Avimor will boast about 10,000 homes and include about 700,000 square feet of mixed use development that will eschew big box retailers in favor of a smaller grocery store and potentially a hardware store, a brewery and a possible veterinary clinic. 

Avimor is adding about 150 homes a year and is closing in on 700 total homes now, Richter said. He expects buildout on the scale he envisions to take 30 years.

Avimor has faced criticism from city of Boise officials and other city and county leaders who worried about building the development so far from emergency services and EMS response, Boise Dev reported. Officials worry about slower emergency response times and not burdening the rest of the surrounding taxbase with paying for the small number of people who live in Avimor and are father from emergency services. 

Since construction began, Richter said two fires started along Idaho Highway 55 and burned right up to the community but did not damage homes. 

“I like to think it was our Firewise planning (that saved homes), but also the Eagle Fire Department did a heck of a job managing the fire,” Richter said. 

Many individual properties in Avimor border or back up to wildlands. Richter said that’s a lot of the appeal. There are more than 100 hundred miles of trails people who live in Avimor have access to. But that wild space is also a reminder of the need to be prepared and vigilant. 

“We knew if we were going to be out here, we would deal with fire and we would have to manage that risk,” Richter said. 


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Clark Corbin
Clark Corbin

Clark Corbin has more than a decade of experience covering Idaho government and politics. He has covered every Idaho legislative session since 2011 gavel-to-gavel. Prior to joining the Idaho Capital Sun he reported for the Idaho Falls Post Register and Idaho Education News. His reporting in Idaho has helped uncover a multimillion-dollar investment scam and exposed inaccurate data that school districts submitted to the state.