How to Create Defensible Space

Firewise Landscaping

We live in an area that, unfortunately, is prone to wildfires that can destroy homes and properties in the blink of an eye.

To help prevent (or at least minimize) this kind of damage, we create a firewise landscape by reducing the amount of flammable vegetation and materials surrounding your home. Cutting out excess plants and trees will increase the moisture and nutrients available to the remaining vegetation, leaving it healthier and greener.

In this article, we cover the different parts (or zones) of a defensible space and how to maximize protection within each zone.

The Home Ignition Zone

The home itself and everything around it up to around 200 feet is known as the home ignition zone. In the foothill communities of Colorado where the risk of wildfire is high, the home ignition zone extends out well beyond the actual home structure.

We divide the home ignition zone area into three zones depending on topography, access to the home, how the home is constructed, vegetation, and property lines. Because each property is different, the measurements used here are only a general guideline. The experienced Arborists here at LAM Tree Service will determine the actual distances for each zone when we visit your property to provide an estimate for creating a firewise landscape.

These three zones, Zone 1, Zone 2 and Zone 3 are treated differently on almost every property - it’s not just a matter of distance from your house.

First and foremost, we take your opinion and needs into consideration, such as keeping your favorite trees and shrubs, or providing privacy screening. Second, we look at how the landscaping influences your property’s value and we do our best not to negatively impact that when recommending firewise precautions. We all live in this area because of its natural beauty; the plants make up a large part of that.

Zone 1 - Creating a Defensible Space Around Your Home

Zone 1 is where the strongest defense is needed from an approaching wildfire or escaping structures fires. This is where any efforts should begin to aid emergency personnel in evacuating you and your family and/or protecting the structure. It encircles the structure and all its attachments (wooden decks, fences, and boardwalks) for at least 30 feet on all sides.

Here are our general recommendations for creating a defensible space in Zone 1:

• Choose plants that are low-growing and free of resins, oils and waxes that burn easily (see our recommendations and tips here). Space them carefully so fire can’t easily spread from one to the other.
• Landscape in this area using non-flammable landscaping materials (such as gravel and rocks) and/or high-moisture-content annuals and perennials.
• Keep the grass mowed low and well watered if possible.
• Prune trees up six to ten feet from the ground.
• Space conifer trees 30 feet between crowns.
• If there are any limbs or branches overhanging the roof, or any branches close to/touching the house, trim them back to at least 10 feet from the house.
• Remove fuel sources close to the house. The perimeter of the home and attachments out to about 5 feet are vulnerable if there is anything there that could ignite and thus allow flames to touch the house.
• Wind-driven fire will create a blizzard of embers that will pile up in corners where you might normally find accumulations of leaves or needles around your home. Keep these corners, nooks, and crannies clear of any flammables.
• Remove dead vegetation or piled wood from under the deck and within 10 feet of your house.
• Consider fire-resistant material for patio furniture, siding, decking, roofing, swing sets, etc.
• Remove firewood stacks and propane tanks; they should not be located in this zone.
• Water plants, trees and mulch regularly.
• Consider xeriscaping if you are affected by water-use restrictions.

Zone 2 – Fire Mitigation Through Fuel Reduction

Zone 2 extends from between 30 to 100 feet from the home. This is the reduced fuels zone where fire mitigation occurs. In the event of an approaching wildfire, a well-managed Zone 2 area discourages rapid burning and crown-to-crown fire movement. The goal of fire mitigation is to effectively slow down or disrupt the progression of the fire before it reaches your defensible space and structures (your home).

For effective fire mitigation in Zone 2, we recommend the following:

• Leave a minimum of 10 feet between clusters of two to three trees, or 15 feet between individual trees.
• Encourage a mixture of deciduous and coniferous trees, varying in age and species. You'll find some suggestions here.
• Create ‘fuel breaks’, like driveways, gravel walkways, patios, mowed field areas, and lawns.
• Prune trees up six to ten feet from the ground, especially dead limbs.

Zone 3 - Maintaining a Healthy Forest

Zone 3 is 100 to at least 200 feet from the home and this area should be thinned, although less space is required between trees than in Zone 2. Occasionally, work in Zone 3 can allow for more density than in the other zones, preserving privacy near the home.

General guidelines for Zone 3 are to:

• Remove smaller conifers that are growing between taller trees.
• Remove any heavy accumulations of woody debris.
• Reduce the density of tall trees so canopies are not touching.
• Use existing fuel breaks like roads, rocky outcrops, riparian and meadow areas.

You have several options when addressing fire danger on your property – fire mitigation is definitely not a “one size fits all” approach. The three zones can be addressed over time as your budget allows and to ensure that property value is maintained.

Look to LAM Tree Service, the area’s most experienced Arborists, to help you build a long-term firewise landscape plan for your forests and outdoor living spaces.