Many
think that a truly defensible space is one that is devoid of all
vegetation, ugly, and sterile. Who wants to looks at that? But, a
fire resistive landscape does not have to be an ugly landscape.
There are many ways to design and install a pleasing landscape that
combines beauty with functionality and protection.
Choosing Fire Resistive Plants
Before discussing reducing fire hazard through plant
material selection, remember – all plants will burn if there
is enough heat and other conditions are right. The term
“fire resistive” is used when referring to plants that are
less flammable than others. The selection of fire resistive
plants is usually far less important than how those plants and other
landscape elements are configured in the landscape, and how those
landscape materials are maintained.
Plant condition is as (or more) important as the
species. Depending on plants’ growth form and access to water and
nutrients, the same species may be fire-resistive in one environment
and combustible in another. Summer irrigation may make the
difference between an extremely flammable plant and one that will
not burn readily.
Plants
that ignite readily and burn intensely, known as pyrophytes
or “fire-prone” plants, typically share certain characteristics.
They:
-
are water-stressed.
-
usually accumulate fine, twiggy, dry, or dead material.
-
have leaves and wood containing volatile waxes, fats, terpenes,
or oils.
-
are typically aromatic (crushed leaves have strong odors).
-
have gummy, resinous sap with a strong odor.
-
are commonly blade-leaf or needle-leaf evergreens.
-
have stiff, leathery, small, or fine lacy leaves.
-
may have pubescent (hair covered) leaves.
-
may have loose or papery bark.
-
are plants that flame (not smolder) when preheated and ignited
with a match.
“Fire-resistive” plants share the following
characteristics. They:
-
have
a high moisture content in their leaves.
-
are drought-tolerant.
-
have little or no seasonal accumulation of dead vegetation.
-
have a low volume of total vegetation.
-
have non-resinous woody material.
-
have an open, loose branching habit.
-
are commonly slow growing.
When planning your
landscape, use the characteristics of fire-resistive and pyrophytic
plants along with site characteristics such as slope, aspect,
hardiness zone, and amount of precipitation to choose plant
materials suitable for your site.
Your plant materials should be well chosen, well
placed and well maintained. Here are a few suggestions for
fire-resistive plant materials:
Landscaping Tips
Here are some landscaping ideas that combine fire
protection with pleasing and practical design elements.
Hardscape Elements
-
Use
hardscape features such as driveways, gravel, concrete, or paved
walks as fire breaks. These firebreaks can be used to separate
foundation plantings from the rest of the landscape, as well as
provide safe and well-defined access to your property and home.
-
Raised
beds made from non-flammable materials such as rocks or bricks
are another good way to create firebreaks between adjacent
landscape areas. Even a short rock wall will provide an
effective firebreak between a lawn and your home, or between
fire protection zones.
-
Use
gravel mulch (versus bark) against any structures and under
decks and porches and in areas adjacent to wooden stairs and
fences. These areas should also be kept free of vegetation and
debris.
-
Clear
excess plant materials from around propane tanks, which should
be placed well away from your home. Also replace wooden fencing
around tanks with non-flammable fencing materials such as chain
link.
-
Foundation plantings should be carefully selected and well
maintained. Plants should be kept low, free of debris, and well
watered.
-
Large,
paved patio areas not only provide effective firebreaks, but
also increase your outdoor living space.
-
Islands
of vegetation in raised beds, surrounded by well-watered turf
allows for a beautiful, and fire resistive, landscape.
Water
-
Your
irrigation system could mean the difference between saving your
home or not. Whether you have an installed, below ground system
with pop-up sprinkler heads or a series of hoses and sprinklers,
make sure they are well maintained. Plan on additional lengths
of hose for placing sprinklers on roofs and decks in the event
of an approaching wildfire. Also consider investing in a
gas-powered generator to run the pump in your well in the event
you loose power.
-
A
well-watered landscape is a fire resistant landscape. Use your
water wisely and concentrate irrigation efforts in the areas
immediate surrounding your home. If you are not able to water
your lawn regularly, keep the turf short.
-
Consider
alterative water sources. Pools and ponds not only look great
and provide recreational opportunities, but make excellent
firebreaks and provide additional sources of water. If you
install (or have) an on-site back-up source of water, make sure
it is well marked and accessible to firefighters.
A well-designed and
installed landscape can greatly increase the chances of your home
and property from escaping destruction from wildfire. But fire
protection doesn’t stop here!
Next -
Part III of the Landscaping for Fire Prevention Series –
Maintaining Your Fire Resistive Landscape.
For additional
information and informative figures and photos, email the
UI Extension Forestry office
and request a copy of Protecting and Landscaping Homes on the
Wildland Urban Interface. by Yvonne C. Barkley, Chris
Schnepf, and Jack Cohen. Station Bulletin No. 67, January, 2005.
Idaho Forest, Wildlife and Range Experiment Station, Moscow, ID.
