4 Tips to Design and Maintain Your Fire-Season Defensible Space Area

To protect your home and other buildings from the threat of wildfires, experts recommend that you develop a plan for the landscaping areas directly surrounding any structures. This area around structures is sometimes called the “defensible space area” or DSA.

In this zone, you’ll eliminate flammable vegetation and trees and replace them with more fire-resistant ground covers and perennials. Below, you’ll find four tips for creating and maintaining the DSA around your property.

Remember: Keep It Lean, Clean, and Green

Many people mistakenly assume that a DSA should be bare dirt around the home. Dirt may seem like a sure way to keep fire from spreading, but it’s not. Pine needles and leaves can collect on the bare soil and be just as flammable as dead shrubbery. Also, leaving dirt bare and unplanted leads to erosion of soil with each storm runoff event, which isn’t good for your property or the watershed.

The DSA should instead be a combination of walkways, lawns, and flower beds. It should be lean, with only a minimal amount of flammable vegetation in the area. It should be clean, meaning you regularly remove dead branches and other fire-feeding debris. The DSA must also be green, using plants that are well-watered and growing during the active wildfire months.

Determine Ideal DSA Width by Your Land Type

If your house is located on a gently sloping lot, you can get away with a DSA that’s 30 feet wide all around the home. If you’re on a moderate or steep slope, or you’re surrounded by forest, the DSA around your home may need to be as wide as 200 feet to be safe.

In this space, you should also remove any trees that are 10 feet or fewer from a power line, chimney, or the house itself. All downed trees, standing dead trees, wood piles, and dried herbaceous plants should also be removed in the DSA. Store your firewood at least 30 feet from your home in an uphill location.

Break Up Continuous Wild or Installed Vegetation

In the wild, plants and shrubs can spread and form a dense cover over an area. If your DSA has a continuous brush field or lots of coniferous trees growing close together, you need to thin this vegetation. Thinning creates distance between growing trees and shrubs so they are less likely to catch each other on fire.

The distance between shrubs should be at least twice the height of the average shrub. For example, if there are 3-foot-tall juniper bushes growing there, you should thin them to at least six feet apart on a gently sloping lot. This distance should be lengthened to four times the height of the vegetation for shrubs on steeper slopes.

Trees should be no closer than 10 feet on flat or slightly sloped ground. For trees on a 21 to 40 percent grade, the distance between them should be no less than 20 feet. On very steep hills and slopes of 41 percent or more, allow no less than 30 feet between trees to maintain the safest DSA.

Choose Native Plants Whenever Possible

Using native plants in the DSA is a wise choice. These are ground covers and herbaceous plants that are well suited to the climate and soil in your area. Your local landscaper knows the best performers for your area, and will help you develop a landscape plan that’s both attractive and fire-resistant.

Lush and colorful plants you can enjoy in your DSA include the following slope stabilizers that are perfect on hills or as ground covers near the home:

• Lupinus breweri or Brewer’s lupine
• Phlox subulata or moss pink
• Saponiria ocymoides or soapwort
• Galium odoratum or sweet woodruff

Blooming plants for beds and native plantings include Western columbine, California poppy, and mountain larkspur. Avoid planting invasive species including Dalmation toadflax and Scotch broom. Ask your landscaping professionals to select your plants for you if you’re unsure about which ones are pests.

The professionals at Estate Landscape know how to develop DSAs, and we’ve installed many successful native plantings in the North Tahoe and Truckee areas. Contact us today to get started on your fresh new landscaping that looks great and offers fire-resistance, too.