Planning your fire-smart landscape.
Everyone living in the West is aware that wildfires are becoming more destructive, and they happen more frequently. Every year more homes are lost because of wildfires. Several organizations have put out helpful information to protect homes.
One of the most important recommendations is to create a defensible space around the home. A defensible space is a buffer that slows down or stops the spread of wildfire. It also provides firefighters with an area that is safer to be in while they try to protect your home. For Oregon check out the following handy check list: Oregon Defensible space for Homeowners & Renters.
A defensible landscape is generally divided into several zones:
Zone 0 extends 5 feet from the home. There should be no combustible materials in this zone, including plants.
Zone 1 extends from 5 feet to 30 feet around the home. In this zone it is recommended to space trees, shrub beds, wood piles and even wooden furniture so that everything that can burn is separated by at least 10 feet. Trees in this zone need to be limbed up. Keep this zone lush and moist with a well-designed low water-use irrigation system.
Zone 2 extends to 100 feet from the home. Dead plant material should be removed regularly from the entire landscape all the way to the property boundary or at least up to 100 feet from the home. In this zone trees should also be spaced and limbed up.
These are excellent recommendations. However, what we have found in our Pacific Northwest landscape architecture practice at LandCurrent, is that many property owners aren’t ready to follow these guidelines. This is especially true if following the guidelines involves removing large mature shrubs and trees. Oregonians simply love their greenery. This made us think that a gradual approach to making a landscape more fire-smart might be helpful. In addition, planning for a fire-smart landscape can go hand-in-hand with other improvements to your landscape such as creating a nice sitting nook to enjoy the sun in early spring. (Note that California now requires homeowners to implement regional defensible space).
Homes in Oregon that are the most in danger of destruction by wildfire are those in or adjacent to forested areas. These Oregon home landscapes often have one or more wood piles as well various landscape structures made out of wood. Wood structures include, decks, fences and gates. The recommendations that follow are for Oregon home owners with a home in or near forested lands.
Clean and prune. An easy first step, and one you must do as soon as possible, is to move wood piles at least 30 feet away from the home and, ideally, not near trees, shrub beds or other wood structures. Combustible materials such as dead plant materials, needles and leaves should be cleared away from the house. Start with the zone that is 5 feet around the house and gradually expand to 30 feet from the house and eventually all the way to 100 feet or the property boundary. Note that woodchips are combustible. In the first 5 feet around the home replace wood mulch with pea gravel mulch or in areas where there is no planting pave or gravel this first 5 feet zone.
Next remove any tree or shrub that touches the house and that you don’t like anyway. Another, not so painful measure is the prune shrubs next to the house away from windows and as low as you can bare. Prune tree limbs at least 5 feet away from the siding, 10 feet from the chimney opening and 10 feet above the roof. Gradually expand your pruning efforts and limb trees up well above the shrubs and plants that grow below them, you can simultaneously lower the shrubs to create even more space between the shrubs and the trees. The beforementioned document from the Oregon State Fire Marshal has nice graphics that can guide your pruning efforts.
Wood structures near the home. Take out the last 5-foot section of wooden fence or gate next to the house and replace it with a gate or fence section that is non-combustible such as a metal gate. Here it is useful to have an overall landscape plan. When you replace the 5 feet section it is good to already have an idea of how you will replace the entire fence in the future. Your wood fence will not last forever and when you do replace it, you want to do it with a non-combustible material that matches that first 5-foot section.
The biggest problem with a wood deck is the debris below it, so make sure that you clean on and below the deck regularly. When replacing a deck consider to use metal framing and use low flame spread deck boards. With new designs consider a paved or gravel patio instead of a deck.
Trees and Shrubs. When you make a plan for your landscape you want to know where you want shrubs and trees. Create your plan keeping fire safety guidelines into account, again using the recommendations from the State Fire Marchal. Here is when you can start separating trees crowns at least 10 feet, as recommended for fire-wise landscape.
You should also consult the Fire-Resistive Plants guide published by several universities including Oregon State University. This guide not only lists fire-restive plants but also has a good description of plants that are highly flammable.
Consider removing any tree that you don’t love anyway and that is not fire-resistant. Note that many conifers are much more flammable than deciduous trees, the ubiquitous Doug Fir is unfortunately a highly flammable tree.
We often see that our priced Oregon White Oak is shaded out by tall Doug Firs. In the process of making your landscape more fire-smart think about giving more space to our oaks at the same time.
When rethinking your landscape consider where you want shade and sun on what time of the day in which season. Perhaps a careful removal of just a few trees will provide you with a sunny spring nook while at the same time creating more space between existing tree crowns.
Irrigation. There is a famous photo that keeps circulating around the internet whenever we are back in fire season. It shows a house with a nice green landscape as an island in an otherwise completely burned down area. The story is that this house was saved because the home-owner turned on the irrigation system when the wildfire approached. This may be an oversimplified story but a well irrigated landscape does contain more moist and can reduce the spread of wildfire. In this age of climate change a well-designed low-water use irrigation system will keep your plants healthy during our increasingly hotter and drier summers.
Having irrigated spaces near to the house while keeping areas further from the house non-irrigated can also provide a beautiful gradual transition from forest or other natural lands to the home. At LandCurrent we often design irrigation systems that slowly go from well-irrigated areas near to house to less and less intensely irrigated zones. The beauty of this is that the less intensely irrigated zones can be set to more frequent watering cycles when there is greater fire danger.
The mower as designer. Keeping vegetation low near to the house is another important fire-wise landscape consideration. The mower is actually a design tool, a mowed meadow has a different feel from a tall meadow and a mowed-out space within a meadow creates a classic parklike feeling.
Conclusion
Creating a fire defensible landscape around your home can be a daunting task. You also might resist the idea of taking your beautiful mature trees and shrubs. A landscape plan can inform you how to gradually create your fire-smart landscape as well as simultaneously improve the esthetics and usability of your home landscape
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