Using Landscaping for Wildfire Protection

We’ve spent this past summer hearing about all kinds of scary wildfires. Now it’s time to hear about the Home Ignition Zone–which has really been around for a while. It was first introduced in the late ’90s by a USDA Forest Service scientist named  Jack Cohen. He had been conducting research into how radiant heat was causing houses to ignite into flame. Now you can benefit from over 15 years of wildfire safety reports with a guide for homeowners to save houses from wildfires. [fire photo by David McNew/Getty Images]

Some of these guidelines will seem pretty obvious. A big part of the initial fire reduction planning involves clearing away flammable vegetation (and other things) from around a house. You’re also expected to keep remaining vegetation that has high moisture content. You’re looking for an area between 100 to 200 feet that needs to be protected as the Home Ignition Zone. Now, within that zone, are three other zones–with the official descriptions as follows courtesy of the National Fire Protection Association

Wildfire Protection Zones

Zone 1

Zone 1 encircles the structure and all its attachments (wooden decks, fences, and boardwalks) for at least 30 feet on all sides. Note: the 30-foot number comes from the very minimum distance, on flat ground, that a wood wall can be separated from the radiant heat of large flames without igniting. In this area:

  • Plants should be carefully spaced, low-growing and free of resins, oils and waxes that burn easily.
  • Mow the lawn regularly. Prune trees up six to ten feet from the ground.
  • Space conifer trees 30 feet between crowns. Trim back trees that overhang the house.
  • Create a ‘fire-free’ area within five feet of the home, using non-flammable landscaping materials and/or high-moisture-content annuals and perennials.
  • Remove dead vegetation from under deck and within 10 feet of house.
  • Consider fire-resistant material for patio furniture, 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 

Zone 2 is 30 to 100 feet from the home, and plants in this zone should be low-growing, well irrigated and less flammable. In this area:

  • Leave 30 feet between clusters of two to three trees, or 20 feet between individual trees.
  • Encourage a mixture of deciduous and coniferous trees.
  • Create ‘fuel breaks’, like driveways, gravel walkways and lawns.
  • Prune trees up six to ten feet from the ground.

Zone 3

Zone 3 is 100 to 200 feet from the home and this area should be thinned, although less space is required than in Zone 2. NOTE: Because of other factors such as topography, the recommended distances to mitigate for radiant heat exposure actually extend between 100 to 200 feet from the home – on a site-specific basis. In this area:

  • Remove smaller conifers that are growing between taller trees. Remove heavy accumulation of woody debris.
  • Reduce the density of tall trees so canopies are not touching.

Learning more about wildfire protection

You can also learn more about each zone from the NFPA’s Firewise Landscaping and Construction Guide. We hate the idea of worrying about overflowing vegetation, but we love the idea of everyone reducing the chances of wildfire damage to their home, property, and loved ones. The NFPA site also offers a Firewise Tips Checklist for Homeowners that will really get us gardening types thinking about our safest options.

We’ve also found lots of great landscaping tips in the NFPA’s Checklist for Homeowners. It covers the best way to remove accumulations between trees, to create spaces that can break up the path of a fire. It’s not the most fun gardening we’ve covered here, but–depending on where you live–it could be the most important.

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