How to make your yard a fire-resistant landscape
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With the snow falling, much of the outside gardening is done for the year. You may be thinking about your yard and dreaming about green grass and big shade trees while the snow flies horizontally from all directions. As you ponder your landscape options come spring, one factor should be a priority in your plans: Fire.
Fire has long had a role in forest and rangeland ecosystems. Fire removes dead and decadent plant material to open space for new seedlings and recycles and makes available important plant nutrients. As more people build homes in and around Idaho’s forests and rangelands, they become part of the natural landscape. What may be a beautiful full landscape in urban areas can become a tinderbox waiting to ignite when surrounded by a native landscape.
Idaho Firewise is an organization that promotes wildland fire education to reduce loss from wildfire. One of their main focuses is to reduce a home’s vulnerability by minimizing and rearranging fuel in the landscape. Three principles should be considered when designing a fire-resistant landscape — defensible space, plant material, and maintenance.
Defensible space is the natural and landscaped area around a structure that is designed and maintained to reduce fire danger. Ignition potential can be influenced by minimizing and rearranging fuels. On flat ground, 100 feet from the building structure is recommended, while 200 feet is recommended on sloped sites.
Three zones or areas surrounding your home should be considered. Zone 1, or the immediate zone is within 5 feet of the home. Zone 1 should include short, succulent flowering annuals or perennials. Replace bark or pine needle mulch with gravel mulch to reduce ignition potential.
Zone 2, 5-30 feet from the home, should consist of a well-maintained greenbelt. Surround any flower beds with rock or brick retaining walls and well-watered turf. Mow regularly to keep the height of lawns under four inches and clear vegetation regularly to keep the landscape “lean, clean, and green.” The importance of regular watering cannot be stated enough. Green plants are much harder to burn than dry plants. Consider using hardscapes like dry riverbeds or water features as a means of beatification. Tree placement should be planned so tree canopies reach no closer than 10 feet to the edge of the home.
Zone 3, 30-100 feet from the home. Sometimes property lines come before the 100-foot line. Make sure to work with your neighbors to protect multiple properties. Remove highly flammable vegetation and replace it with fire resistant species. Maintain zone 3 by removing dead and dying plants, thinning and pruning, and periodic fertilization and irrigation as needed. Stack firewood and propane tanks a minimum of 30 feet from the home and surround it with a nonflammable fence. Trees 30-60 feet from a home should have a 12-foot gap between canopy tops, and trees 60-100 feet from a home should have a gap of 6 feet between the canopy tops.
Any plant will burn if conditions are right. Plant condition is more important than species. Access to water and nutrients can determine the conditions much more than the species or the growth form of the plant.
Fire resistant plants often have higher moisture content in the leaves, have little seasonal buildup of dead vegetation, have low, compact growth forms, have a higher pectin content, have green stems, and are drought tolerant.
Maintenance is the key to keeping your landscape resistant to fire. In Zone 1 you want to “clean and green.” Spend most of your time supporting this area by regularly irrigating, removing spent flowers, or dying foliage, and sweeping and raking flammable debris from walkways, patios, and planting beds.
Zone 2 should be “pruned and groomed.” A well-maintained turf is very fire resistant. It is best to keep the lawn green, but if there is a lack of water keep it trimmed low, especially close to structures. Maintain trees and woody shrubs by pruning dead and dying branches and thinning to keep space between plants.
Zone 3 will have the least amount of attention during the growing season. A good maintenance plan should include pruning trees and shrubs to ensure adequate spacing. Controlling unwanted vegetation and invasive weeds to reduce ignition potential will be important because a lack of irrigation will cause grasses to become flammable.