Wildfire and your Home

In order to understand the effect wildland fires have on and structures, the Insurance Institute for Business and Home Safety Research Center created a controlled environment for simulating the effects of a wildland fire on a structure. By using a wide variety of commonly used home building materials they were able to accurately demonstrate what can happen to a home when exposed to ember bombardment. This type of event is common during wind driven wildfires. It is important to note that there are no direct flames from the ember source contacting the structure. This test is specifically designed to test building materials to embers and not direct flames.

A common misconception of why homes are lost in wildfires is the assumption that the "wall of flames" on the fires leading edge was the reason all homes are lost in a wildfire event. Fire scientists and wildland fire specialists have determined that in fact it is possible that more homes are lost in a wildfires due to ember intrusion into the structure through vents and crawlspaces, embers landing in gutters and igniting built up leaf litter and flammable material against the edges of homes. This video shows the results of mulch burning around the base of the home and the resulting effects on the structure once the mulch has ignited it. This video is a good reminder of why a homes defensible space is much more than landscaping and that small improvements, such as adding 1/16'' mesh screening to attic vents, can make a huge difference in a homes ability to withstand an approaching wildfire.

TO PLANT, OR NOT TO PLANT???

We are often approached by homeowners with the question of acceptable landscape plants in the high fire hazard area. While our webiste has a comprehensive list of recommended plants (avalible here), there are also a number of specific plants that are NOT recommeded. Below is an excerpt from the City Fire Departments High Fire Hazard Area Landscape Requirements (Ordinance #5439).  The full print out can be found through the City's website or by clicking this link.
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Certain plants are considered to be undesirable in the landscape due to characteristics that make them highly flammable. These characteristics can be either physical or chemical. Physical properties would include large amounts of dead material retained within the plant, rough or peeling bark, and the production of profuse amounts of litter. Chemical properties include the presence of volatile substances such as oils, resins, wax, and pitch. Certain native plants are notorious as species containing these volatile substances.

Plants with these characteristics should not be planted in High Fire Hazard areas. They are referred to as target species since their partial or complete removal is a critical part of hazard reduction. The following is a list of plants that are not allowed to be planted within the landscape zones defined below:

Unacceptable Plant Species:
Acacia species
Adenostoma fasciculatum – Chamise
Adenostoma sparsifolium – Red Shank
Artemesia californica – California Sagebrush
Baccharis species (low growing form OK)
Casuarina species - Beefwood
Cortadera species – Pampas Grass
Cupressus species – Cypress
Eriogonum faciculatum – Common Buckwheat
Eucalyptus species – Eucalyptus
Juniperous species – Juniper (except species which grow less than 1ft)
Olneya tesota - Iron wood
Pennisetum - Fountain Grass
Pinus species – Pine

Other plants may be considered undesirable because of their ability to naturalize and become a pest. These types of plants should be avoided, especially in sensitive riparian or coastal areas where they could become established and compete with native vegetation.