Using landscaping and maintenance to defend against the next wildfire
By Brian Torone, Torone Consulting
By Brian Torone, Torone Consulting
[This is part two of a three-part series.]
In part one of this series, we explored how to build or remodel homes to defend against wildfire. But how can the area around the home be used to defend against the flying embers and ground fires that lead to the catastrophic loss of homes? The recommendations of the National Fire Protection Association (NFPA), Cal Fire, as well as architects, firefighters and industry experts (as summarized below) have shown that we can protect our homes using defensible space and drastically reduce our fire risk.
The Immediate Zone: From 0-5 feet around the housePlants, trees, and mulch in this zone can ignite your siding, eaves or roof. In windy conditions, small embers from this area can fly into foundation and roof vents. Thus, this zone should be completely free of trees, shrubs, pine needles, leaves, planter boxes, and firewood. Propane tanks, flammable lawn chairs, cushions, and doormats should not be kept in close proximity to the house. In addition, bark and other flammable mulches should be avoided in this zone.
Non-combustible materials should be used to the greatest extent possible. Great materials to use are rock, gravel, crushed granite and concrete walkways. If plants are used, they should be as small as possible, irrigated, and planted in stone or gravel.
The Intermediate Zone: From 5-30 feet from the houseThe goal in this zone is to reduce the amount of fuel and to prevent a fire from moving toward your house. Keys to this include:
• Creating fuel breaks with driveways, walkways and patios.
• Limiting shrubs and trees.
• Keeping lawns mowed to no more than four inches. Green lawns generally do not catch fire. Dried grasses do.
• Pruning large trees at least six feet above the ground, and more if practical. Trees with low limbs catch fire much more easily than pruned trees.
• Clearing small shrubs and trees growing under larger trees. The flames from shrubs can catch the trees above them on fire.
• Spacing trees far apart so that trees don’t catch each other on fire. The NFPA recommends a minimum of 18 feet between tree crowns (i.e., having 18 feet between any part of a tree and any part of an adjacent tree).
• Raking all leaves. This is especially important in the late summer and fall when we have the combination of hot weather, dried out vegetation and leaves on the ground.
The Extended Zone: From 30-100 feet from the houseIn this zone, tree crowns should be at least six to 12 feet apart. Sheds should be as far away from the house as possible.
The trunks of large trees near your house are generally not a fire hazard, but the leaves, needles, and twigs that trees drop can create major problems. Rake and remove them.
Keep all trees trimmed so they don’t come in contact with electrical wires. Utilities can’t be relied upon to do this. Install electrical lines underground, if possible.
Again, bark is bad, grass is good, and hardscaping is best.
Important notes for the three zonesIf your home sits on a steep slope, standard protective measures may not suffice. Fire moves quickly up steep slopes, so larger safety zones may be necessary.
Many people will be planting new trees during the reconstruction effort. For fire safety, hardwood, maple, poplar and cherry trees are more fire-resistant than pine, evergreen, eucalyptus, or fir. Some of the worst trees in the Kenwood fire were palm trees; that’s because fire burned up the trunks, then caught the fronds on fire. In the high winds, embers from the fronds shot long distances from the tops of the palms.
For plants and shrubs, many fire resistant species are available. An excellent website for further information on these species and on fire preparedness is readyforwildfire.org.
Fire resistance around the houseAdditional items to consider to make the area around your house fire resistant include:
Clearing a 10-foot area around propane tanks and the barbecue.
Stacking firewood as far away from the house as possible and uphill from your home.
Providing water hoses that reach the entire area around your house. In a fire, you may be able to fight small fires, or delay their effects until emergency responders arrive on the scene.
Having a fire extinguisher handy, knowing where it is, and knowing how to use it. Different extinguishers operate in different ways, and many people have never used theirs. There is no time to read directions during an emergency.
Keeping a ladder handy that will reach the roof. You may need to get on the roof to wet it down or remove flammable debris.
Keeping household items handy that can be used as fire tools: a rake, ax, hand saw or chainsaw, bucket, and shovel.
ConclusionThe keys to creating a defensible space around your home are to reduce the amount of fuel around it, and to have nothing that will ignite next to it. This is the best way to starve a fire so that your home will have the best chance of surviving. In Kenwood and other fire areas, we have new opportunities to implement these strategies and keep our community as safe as possible.
Brian Torone is an architect who lives in Kenwood.