Things to know about fire, nature and our relationship with both…
I recently was introduced to the work of the Chaparral Institute in our quest to understand fire and peoples’ relationship with fire. There is a lot of misinformation, or more specifically, missing information about protecting one’s home from fire. During a recent phone conversation with Rick Halsey of the Chaparral Institute, my concerns about destruction of native habitat to “create defensible space” were confirmed. We will be sharing more about what we learned in the near future, but for now check out this enlightening piece by Rick.
From Fire and Chaparral in Southern California
by The Chaparral Institute
The California Chaparral Institute along with researchers through the USGS and the Conservation Biology Institute have a series of articles that quantify some of the most effective ways of protecting your home from fire. A good way to think about fire in southern California is ‘start from the house out, not the wildland in.’
While there is not one single answer to fire protection, there are 3 major factors at play:
1. Flying embers are what ignite homes.
The ignition source of most homes burned in a wildfire is the embers carried by strong winds. Fire will find the weakest link, if there is something on or near the home that can be ignited, it will. Homes that have adequate defensible space (100 ft or more) have still burned when embers ignited something near or within the house.
Small scale precautions can be taken at the homeowner level to protect yourself from embers entering your home and causing it to ignite. Having vegetation that has been lightly irrigated on the landscape absorbs some of the hot embers that would all be blown towards the house otherwise.
Exterior Sprinklers provide an additional method to protect the home from ignition from embers. They need to be coupled with an independent pump and water supply like a pool or water tank.
Ember Resistant Vents can prevent small embers from getting into the house and igniting it from within.
2. It’s not the wildland vegetation, it’s the location.
The location and the surrounding areas of a home can have a significant influence on the risk that a home is facing from fire. The 3 main determining factors: steep slopes, homes in wind corridors, and low density developments in less developed areas. Areas that had high amounts of grasses or other non-native annuals were more likely to burn than areas that had native habitat like chaparral.
3. Defensible space can work, but beyond 100 feet it is counter productive
A study in 2014 headed by Syphard and Keeley found that:
- The most effective way to reduce structure losses is to reduce the percentage of woody cover up to 40% next to the structure, and make sure that no vegetation overhangs or touches the structure.
- There is no additional protection from clearing beyond 100 ft, and the most important treatment zone is 16-58 ft from structures.
- The amount of cover reduced is as important as the distance from a structure, but complete removal of vegetation is not necessary. Think of it as fuel modification instead of clearance.
OK, so what should I do around my house if I live in a fire prone area?
- Ensure that the first 30 feet around the home has no flammable materials and is landscaped with fire resistant plants. Las Pilitas has the best resources on flammability and plant selection: https://www.laspilitas.com/classes/fire_burn_times.html
- Native vegetation surrounding structures beyond the first 30 feet should be managed to remove dead wood, and have a loose canopy, with an effort to not disturb the soil, as soil disturbance can give way to non-native flammable weeds. A good example is here, from the city of San Diego.
- Make sure the home has fire resistant roofing, proper attic vent covers, enclosed eaves, and exterior sprinklers.
All items mentioned in this article are referenced and compiled from http://www.californiachaparral.org/bprotectingyourhome.html
–Sarah P. Fisher
Sarah Fisher has a B.S. in Wildlife Biology from Humboldt State University, and is currently in her second year of her Masters in Landscape Architecture at Cal Poly Pomona. She is an avid hiker and naturalist, with a passion for California native ecosystems.