Wildfires and Defensible Space

 

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Email:  Housecheck@mchsi.com


God Bless America!
 

Although it can happen any time, this is the season for wildfires.   And, although it can happen anywhere, California is known for wildfires.  We have recently suffered from wildfires in our area, Clearlake Oaks Fire and the Blue Lake Fire.

 

Many people wonder what reasonable precautions they can take to defend their homes against wildfires that pop up from time to time almost everywhere here in Northern California.  Generally, they last no more than a few hours and taking a few steps to ensure that your property has a chance of surviving intact is certainly worth the trouble.

 


California Wildfire

WHAT IS DEFENSIBLE SPACE?

Defensible space is the area between a house and an oncoming wildfire where the vegetation has been modified to reduce the wildfire threat and to provide an opportunity for firefighters to effectively defend the house.  Sometimes, a defensible space is simply a homeowner’s properly maintain backyard.

WHAT IS THE RELATIONSHIP BETWEEN VEGETATION AND WILDFIRE THREAT?

Many people do not view the plant growing on their property as a threat.  But in terms of wildfire, the vegetation adjacent to their homes can have considerable influence upon the survivability of thei houses.  Al vegetation, including plants native to the area as well as ornamental plants, is potential wildfire fuel.  If vegetation is properly modified and maintained, a wildfire can be slowed, the length of flames shortened, and the amount of heat reduced, all of which assist firefighters in defending the home against an oncoming wildfire.

THE FIRE DEPARTMENT IS SUPPOSED TO PROTECT MY HOUSE, SO WHY BOTHER WITH DEFENSIBLE SPACE?

Some individuals incorrectly assume that a fire engine will be parked in their driveway and firefighters will be actively defending their homes if a wildfire approaches.  During a major wildfire, it is unlikely there will be enough firefighting resources available to defend every home.  In these instances, firefighters will likely select homes they can most safely and effectively protect.  Even with adequate resources, some wildfires may be so intense that there may be little firefighters can do to prevent a house from burning.  The key is to reduce fire intensity as wildfire nears the house.  This can be accomplished by reducing the amount of flammable vegetation surrounding a home.  Consequently, the most important person in protecting a house from wildfire is not a firefighter, but the property owner.  And it’s the action taken by the owner before the wildfire occurs (such as proper landscaping) that is most critical.

DOES DEFENSIBLE SPACE REQUIRE A LOT OF BARE GROUND IN MY LANDSCAPE? 

No.  Unfortunately, many people have this misconception.  While bare ground is certainly effective in reducing the wildfire threat, it is unnecessary and unacceptable due to appearance, soil erosion, and other reasons.  Many Homes have attractive, well vegetated landscapes that also serve as effective defensible space.

DOES CREATING A DEFENSIBLE SPACE REQUIRE ANY SPECIAL SKILLS OR EQUIPMENT?

 No.  For the most part, creating a defensible space employs routine gardening and landscape maintenance practices such as pruning, mowing, weeding, plant removal, appropriate plant selection and irrigation.  Equipment needed includes common tools like a chain saw, pruning saw, pruning shears, loppers, weed-eater, shovel and a rake.  A chipper, compost bin or a large rented trash dumpster may be useful in disposing of unwanted plant material.

 

 

Another Home Devastated by a California Wildfire

HOW BIG IS AN EFFECTIVE DEFENSIBLE SPACE?

Defensible space size is not the same for everyone, but varies by slope and type of wildland vegetation growing near the house.

a.       Flat to Gently Sloping 0 to 20%, 30-50 feet for wildland grasses and weeds, 100 feet for shrubs, and 30 feet for trees unless there is substantial grass and shrub underneath, then use the value for shrubs.

b.      Moderately Steep 21% to 40%, 100 feet for wildland grasses and weeds, 150 feet for shrubs, and 100 feet for trees unless there is substantial grass and shrub underneath, then use the value for shrubs.

c.       Very Steep 40% or more, 100 feet for wildland grasses and weeds, 150 feet for shrubs, and 150 feet for trees unless there is substantial grass and shrub underneath.

DOES DEFENSIBLE SPACE MAKE A DIFFERENCE?

Yes.  Investigations of homes threatened by wildfire indicate that houses with an effective defensible space are much more likely to survive a wildfire.  Further, homes with both an effective defensible space and a nonflammable roof (composition shingles, tile, metal, etc.) are many times more likely to survive a wildfire than those without defensible space and flammable roofs (wood shakes or shingles).  Appropriate roofing materials and defensive space give firefighters the opportunity to effectively and safely defend the home.