With the snow falling, most of the outdoor gardening is done for the year. You may be thinking about your yard and dreaming of green grass and big shade trees while snow flies horizontally from all directions. As you contemplate your landscape options come spring, one factor should be a priority in your plans: Fire.
Fire has long played a role in forest and mountain ecosystems. Fire removes dead and decaying plant material to open up new seedlings and recycle and utilize essential plant nutrients. As more and more people build homes in and around Idaho’s forests and mountains, they become part of the natural landscape. What might be a beautiful landscape in urban areas can be a tinderbox waiting to ignite when surrounded by a native landscape.
Idaho Firewise is an organization that promotes wildland fire education to reduce losses from wildfires. One of their main focuses is to reduce the vulnerability of a home by reducing and rearranging fuel in the landscape. Three principles should be considered when designing a fireproof landscape – protected space, plant material, and maintenance.
Defensible Space
Defensible space is the natural and landscaped area around a structure that is designed and maintained to reduce the risk of fire. Burning potential can be influenced by reducing and sorting fuels. On flat land, 100 feet from the building structure is recommended, while 200 feet is recommended on sloping sites.
Three zones or areas surrounding your home should be considered. Zone 1, or the immediate zone is within 5 feet of the house. Zone 1 should include short, succulent flowering annuals or perennials. Replace bark or pine needle mulch with gravel mulch to reduce fire potential.
Zone 2, 5-30 feet from the house, should have a well-maintained greenbelt. Surround any flower beds with stone or brick retaining walls and well-drained lawn. Regular mowing to keep weeds under four inches tall and clear vegetation regularly to keep the landscape “thin, clean, and green”. The importance of regular watering cannot be overstated. Green plants are more difficult to burn than dry plants. Consider using hardscapes such as dry riverbeds or water features as a means of beatification. Tree placement should be planned so that tree canopies extend no less than 10 feet to the edge of the house.
Zone 3, 30-100 feet from home. Sometimes property lines come before the 100-foot line. Be sure to work with your neighbors to protect many properties. Remove highly flammable plants and replace them with non-flammable varieties. Maintain zone 3 by removing dead and dying plants, thinning and pruning, and periodic fertilization and irrigation as needed. Stack fuel and propane tanks a minimum of 30 feet from the house and surround them with a fireproof fence. Trees 30-60 feet from a house should have a 12-foot gap between the tops of the canopy, and trees 60-100 feet from a house should have a 6-foot gap between the ends of the canopy.
Plant Materials
Any plant will burn if the conditions are right. The condition of the plant is more important than the species. Access to water and nutrients can determine conditions more than species or plant growth form.
Fire-resistant plants usually have higher leaf moisture, have less seasonal build-up of dead plants, have low, compact growth forms, have higher pectin content, have green trees, and drought tolerant.
Landscape Maintenance
Maintenance is the key to keeping your landscape fire resistant. In Zone 1 you want to be “clean and green.” Spend most of your time supporting this area by watering regularly, removing spent flowers, or dying leaves, and sweeping and destroying flammable debris from driveways, patios, and planting bed.
Zone 2 should be “dull and smooth.” A well-maintained lawn is less prone to fire. It is best to keep the lawn green, but if there is a lack of water keep it low, especially near structures. Maintain trees and shrubs by pruning dead and dying branches and thinning to maintain space between plants.
Zone 3 has the least attention during the growing season. A good maintenance plan should include pruning trees and shrubs to ensure adequate spacing. Controlling unwanted plants and invasive weeds to reduce fire potential is important because lack of irrigation can cause weeds to catch fire.
