April is wildland urban interface (WUI) month, during the month we would like to take the time to help create and sustain a fire-adapted
community that may lie within the WUI.
First, let’s discuss just what the WUI is. The wildland urban
interface is an area where human-made structures and infrastructures (cell
towers, water supply facilities, etc.) are in or next to areas prone to
wildfire. Some people may think that we don’t have a WUI problem here in PA or
that WUI fires only occur in the western states…but let’s throw some statistics
out there:
·
More than 46 million residences in 70,000 communities
in the US are at risk for WUI fires (U.S. Department of Homeland Security).
·
The WUI area continues to grow by approximately two million
acres per year (U.S. Department of Homeland Security).
·
States with the greatest number of houses in the
WUI (U.S. Forest Service):
1.
California
2.
Texas
3.
Florida
4.
North Carolina
5.
Pennsylvania
This week we would like to focus on helping you create
what’s called defensible space. A defensible space is an area around a
building in which vegetation, debris and other types of combustible fuels have
been treated, cleared, or reduced to slow the spread of fire to and from the
building. You can determine the Fire Severity Zone of an area by looking at
simple factors like local vegetation, weather, and topography, knowing your fire
severity zone will help determine the most effective design of your defensible
space.
A defensible space is one of the most cost-effective ways to protect a
building from a wildfire – and often can be created by the landowner
themselves.
The simplest things you can do are trim branches that
overhang your home, porch, and deck. Keep plants, trees, and branches at least 5
feet from your home.
You should also clear leaves and branches from roofs,
gutters, porches, and decks. Remove dead plants, leaves, and branches at
least 10 feet from your home.
Landscape vegetation can be just as combustible as wildland vegetation
(grass, brush, and timber). If you are concerned about whether your
plants are combustible, there are several characteristics that combustible
vegetation has:
·
Volatile resins and oils (generally aromatic
when crushed)
·
Narrow leaves or long thin needles
·
Waxy or fuzzy leaves
·
Accumulation of dead leaves or twigs on or under
the plant (I clean out my yucca plants every year because they accumulate all
these things naturally)
·
Loose or papery bark
General guidance for creating your defensible space is that
you assess both the horizontal and vertical aspects of vegetation – to prevent
horizontal spread of wildfire thin shrubs and trees so the crowns do not
intersect and there is space between the individual shrubs/trees; for vertical
spread prevention keep the lowest tree branches pruned and trimmed to maintain
vertical separation from tops of shrubs and grass to the lowest tree branches.
There are three concentric zones around a building: Zone 1
will require the most need for fuel modification, and is within 30 feet of the
home, Zone 2 is from 30-100 feet from the home – ideally, you should keep your
woodpiles within this zone., and Zone 3 is anything further than 100 feet from
your home. If you are in a higher Fire Severity Zone your circles should be
larger – consult your local or the state fire agency for assistance in
determining this.
Some final thoughts you should consider are consulting local
or state fire agencies or a qualified fire management specialist about codes,
requirements and standards related to defensible space; as well as planting
low-maintenance plants when sprucing up your landscape:
·
Drought-resistant
·
Pest-resistant
·
Native to the area
·
Noninvasive
·
Slow-growing
·
Wind-resistant
·
Sustainable without supplemental fertilization
Keep in mind that vegetation modification must be performed
in compliance with local, state, and federal environmental regulations.
For further details about what needs to be done within the
zones in your defensible space please click
here.
