Wildfire Mitigation for Homes

The enormous power of wildfires can be devastating. While much of the Rocky Mountain region confronts an historic fire season, tragic lessons are being learned. Many of us living in urban neighborhoods used to think we were safe when grasslands and forests burned near us, but the firestorm that engulfed West Colorado Springs proved those assumptions wrong.

Crack fire crews were ready, air tankers had dropped tons of fire retardant slurry, national experts put a good defensive plan in place, and sudden, erratic, unanticipated 65 mile per hour winds made all of that irrelevant. Entire neighborhoods were erased in minutes. A firestorm overwhelmed all preparations and incinerated hundreds of houses. These weren’t houses sitting solitary in a forest. They were homes sitting side by side along wide streets with sidewalks, playgrounds, and fenced backyards.

I was in Colorado Springs the afternoon of June 26, 2012, and felt sickened by the sight of flames cresting the ridge line that was perceived by all of us as a critical border between the city and the threat beyond. I wasn’t overly worried because I knew the fire crews were ready based on the many updates we were following on the news channels. Upon arriving home, 20 miles east of the danger, I told my wife the fire was worse. It was a sorrowful understatement.

The best-trained, professional, defensive fire teams in the world can be defeated when Mother Nature adds enormous destructive energy to an already devastating force of nature, but those events aren’t common. The Colorado Springs fire is being described by career firefighters as”epic”, with growth patterns and expansive actions previously unseen.

This tragedy has many of us reviewing our own homes and neighborhoods with an eye toward the threat of fire. The idea of “wildfire mitigation” was previously unknown or ignored by many homeowners, but now is the discussion topic at the dinner table.

A wildfire is an uncontrolled burning of grasslands and woodlands, or prairies and forests. The large majority of urban settings are still safe from wildfires, but houses and neighborhoods that border zones of bone-dry vegetation should be aware of practices to reduce the fire threat. Wildfire mitigation for a homeowner involves taking actions to lessen or eliminate the potential damage from a wildfire.

A primary factor in determining a home’s ability to survive a wildfire is the “defensible space” around it. This defensible space is the area of vegetation around a building that can either hinder or fuel a fire. Gardeners are uniquely qualified in determining the appropriateness of such vegetation.

A house is more likely to resist a wildfire if overgrown grass, dried brush, and overhanging trees are thinned or removed from the immediate vicinity of the building. With no or little fuel, a wildfire’s progress can be slowed when it approaches.

Extending a clear space around a structure provides firefighters room to work as they fight flames, keeping a structure fire or a wildfire from moving to other structures or to surrounding woodlands. Giving the trained defenders a defensible space can make the difference between success and failure.

When viewing the area around your home and analyzing the defensible space, think horizontally and vertically. The horizontal space runs across the ground and encompasses low vegetation that could be potential fire fuel. The vertical space runs from the ground to the top of bushes and trees that might ignite. Vegetation that provides both high horizontal and vertical fuel potential poses the biggest threat; thick stands of brush and tightly-packed trees can be hazardous.

Mitigation of wildfire for homes involves disrupting the natural continuity of these horizontal and vertical fuel sources. Thinning large shrubs and trees so there is at least 10 feet between crowns reduces the potential of wildfire moving from one plant to another. Removing low branches and smaller plants under a tree removes these “ladder fuels” that can transform a low, grass fire into a high, tree fire.

A few years ago I was fortunate to receive forestry training as part of our Master Gardener program. It included education on wildfire mitigation and creating defensible zones around houses. I garden using many of those concepts. I’ve worked to prune lower branches off trees near the house to a height of about 10 feet. I don’t plant shrubs near trees. I keep the grass within 100 feet of the house no higher than six inches. Dead trees and branches are removed quickly. No logs or wood are stored within five feet of the house and nothing is stored under the deck.

Even with my education and awareness a wildfire mitigation analysis shows deficiencies and potential hazards in my landscape. I was aware of some of them, overlooked others, and discovered new concerns.

My gardening activities focused on my backyard. Many earlier problems with potential wildfire fuels were corrected. It now offers a substantial defensive space and is maintained well. Little needs to be done there.

A good defensible space

The front of the house has the road and gravel driveway as fire barriers and the old Ponderosa Pine is pruned up to about 15 feet; it is not threatened by a slow-moving, low fire. But there are Aspens and shrubs that abut the exterior walls. They are thick and not pruned as well as they should be. We like the way they look but in a wildfire situation they pose a danger to our home. This is the first place in our landscape where a decision needs to be made between aesthetics and safety. It’s difficult sacrificing landscape plants, but it may be necessary to mitigate fire danger.

Obvious fire mitigation concerns

A similar situation exists on the north side of our house. Open pasture leads to the lawn, a thick stand of Aspens grows about 20 feet from the structure, overgrown bushes rest against the house, and a lone Ponderosa Pine rises within 10 feet of the deck and house. Though the lower branches are removed, the tree poses a serious threat. If it were to catch fire from a wind-blown ember, it threatens both the wood deck and the house. It is now a priority for removal.

Close growth is the main concern

The worst situation is on the south side. Our neighbor’s thick brush and numerous trees flow into a space filled with pine trees on our property that grow right up to the house. Their branches intermingle. There is nothing to stop flames from spreading between them and to our roof.

Serious concerns in this zone

The first defensible zone around a house should extend at least 15 feet around it. All flammable vegetation should be removed from this zone for maximum fire prevention. The second zone extends to at least 75 feet. Within this zone the continuity and arrangement of vegetation should be adjusted to reduce fuel potential. The south side of my home breaks all the rules of creating a wildfire-defensible space.

Many people move to the country or into the forest because they enjoy the scenery and wish to be engulfed by the plants and trees. No one expects that their home will be annihilated by a wildfire. We are now confronted by this obvious possibility.

In the early days of the Waldo Canyon fire as it threatened Colorado Springs, news crews and commentators highlighted the structures that remained immune to the widening fire lines. These homes were in the heart of the forest but they had obvious tree-free zones extending well beyond their walls. The grasses caught fire as the onslought approached but they were easy to extinguish. These homeowners who practiced serious wildfire mitigation practices saw their houses spared.

Creating defensible zones as part of wildfire mitigation works. It needs to exist on a large scale to be most effective. And an entire neighborhood needs to be involved. You can do what you can to reduce fire threat in your landscape but a neighbor’s recklessness can still spell disaster.

I’m working with our homeowner’s association, of which I’m a board member, to address this issue in our community. Already we’re discussing plans for teams to help neighbors remove dead trees and brush if they’re not able to do it on their own.

Many fire stations offer help in fire mitigation. If they have the resources they’ll be happy to examine your landscape and identify problems. Believe me, it is beneficial for them to have defensible space around the homes they protect.

Mother Nature always has the last word. Even the best-defended home can be lost in a firestorm, as we saw this week. In a typical wildfire, wise mitigation practices can prevent loss. Educating yourself becomes critical when confronted by sustained drought as much of the U.S. is facing. High winds  and catastrophic low humidity increase danger. When the fire approaches it is too late to prepare your landscape. Think and act in advance to protect your home.

For more information read these fact sheets from Colorado State University:

Creating Wildfire-Defensible Zones, no. 6.302
Fire-Resistant Landscaping, no. 6.303
Forest Home Fire Safety, no 6.304
Firewise Plant Materials, no. 6.305


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