Week 4: Create Defensible Space Closest to Your Structure – Zone 0

It’s Week 4 of #FirePrepFriday, and this week I was inspired by the news stories I’m seeing about creating defensible space around the structures where we spend most of our time.

This San Francisco Chronicle article, written by reporter Julie Johnson and originally published on April 10th, is one such example of the reports coming out about Berkeley, CA. The Berkeley City Council met last Tuesday to discuss a proposal to pursue the creation of defensible space around homes in neighborhoods near Tilden Regional Park, an area considered to have high fire danger (Johnson, 2025). The City Council proposal is similar to one being developed by the State of California and, in addition to sharing a lot of good information, writes “Best practice requires removing flammable materials and maintaining vegetation to minimize wildfire exposure, particularly within the critical Ember Resistant Zone (Zone 0) and surrounding Home Ignition Zones 1 and 2. These measures require elimination of all combustible materials from within 5 feet of a structure, including vegetation and accessories” (Berkeley City Council, 2025).

What is Zone 0?
Zone 0, the space between 0 and 5 feet from a structure, is not a new concept. To learn more, I recommend reading through CAL FIRE’s Defensible Space webpage. They write that “The intensity of wildfire fuel management varies within the 100-foot perimeter of the home, with more intense fuels’ reduction occurring closer to your home. Start at the home and work your way out to 100 feet on your property line, whichever is closer. … The first five feet from your home is the most important. Keeping the area closest to buildings, structures, and decks clear will prevent embers from igniting materials that can spread the fire to your home. Why? The majority of homes lost to wildfire are ignited by flying embers. Embers can travel miles ahead of the active fire front of wildfires” (CAL FIRE).

If you’re wondering if the concept of Zone 0 is just a fad or if 5 feet was a random decision, the answer is no. It’s supported by science. Three scientists I greatly admire – Drs. Alexandra Syphard, Teresa Brennan, and Jon Keeley – published the results of their 2014 work and found “Structures were more likely to survive a fire with defensible space immediately adjacent to them. The most effective treatment distance varied between 5 and 20 m (16-58 ft) from the structure, but distances larger than 30 m (100 ft) did not provide additional protection, even for structures located on steep slopes. The most effective actions were reducing woody cover up to 40% immediately adjacent to structures and ensuring that vegetation does not overhang or touch the structure” (Syphard, Brennan, and Keeley, 2014). Several studies have been published by these and other top wildfire science researchers in the field – definitely check out the work being shared by places like the Berkeley Fire Research Lab and the Missoula Fire Sciences Laboratory, too. There are many organizations doing incredible work.

What Can You Do in Your Zone 0?
Have I convinced you to inspect Zone 0 and make some changes? Great! Here are just a few things you can do to get started (this is not an exhaustive list):

• Replace combustible wood chips/bark/mulch with stone, gravel, pavers, or concrete
• Remove all dead and dying plants, weeds, leaves, and needles. (Re)move or replace all adjacent vegetation types that are known to be extremely flammable, such as dry palm tree fronds, cypress, and junipers.
  • Here is additional information about fire-hazardous plants from Fire Safe Marin and here is a resource from Kensington Fire that lists drought tolerant, fire resistant, and highly flammable plants
• Remove all tree branches or decorative features within 10 feet of any chimney or stovepipe outlet
• Relocate firewood and lumber to Zone 2 (30 or 50 (depending on your area)-to-100-feet away from the structure)
• Replace combustible fencing materials with non-combustible alternatives like concrete or metal
• Move parked vehicles away from this zone
• Replace natural fiber doormats, wood or plastic patio furniture, and flammable shades or screens with accessories made from non-combustible or ignition-resistant materials. Choose a heavy rubber doormat and cast aluminum furniture
  • Here are more ideas from Fire Safe Marin
• Request an inspection
  • CAL FIRE offers this tool to submit a Defensible Space Inspection Request for homes in parts of California
  • Check to see what your area offers by searching the Web with a phrase like “[Your City Name] defensible space inspection fire department”

If you live in an apartment or rent your home, you should still advocate for a safer space. Check out everything within Zone 0 of the structure and, if you identify any of the “remove” and “replace” items listed above, contact your landlord, property manager, neighborhood Homeowners Association, etc. It’s also in their best interest to keep their property ready for wildfire. And I encourage you to speak up at your workplace, too.

The 0-to-5-foot buffer from your home isn’t that big of a space, but it’s a critical zone. If you love plants and greenery, your yard will still be beautiful even when it starts 5 feet away. The creation of defensible space is extremely important in the event of wildfire, it’s better for the integrity of the structure (particularly in the case of vines), and it prevents unwanted critters from gaining easy access to your home. “Adequate defensible space acts as a barrier to slow or halt the progress of fire that would otherwise engulf your property. It also helps ensure the safety of firefighters defending your home. Defensible space is the first line of defense for your home against wildfire” (CAL FIRE).

Cost: $0 - $$$$$ (depending on whether anything needs to be removed from Zone 0)
Frequency: Ideally, this is a one-time update to a property. Of course, it's always important to remove any encroaching vegetation or new objects that get added over time.

As this week’s task is focused on Zone 0, you may be wondering about home hardening steps. Don’t worry, we’ll get to those in a future #FirePrepFriday.
 
What does Zone 0 look like around your home or workplace? What changes can you make today to create a defensible space? Let me know in the Comments.

References

• Johnson (April 10, 2025) “Berkeley poised to ban most plants within 5 feet of homes deemed a fire risk.” San Francisco Chronicle. Link: https://www.sfchronicle.com/california-wildfires/article/berkeley-fire-zone-zero-20259566.php
• Berkeley City Council (April 15, 2025) “Proclamation Calling a Special Meeting of the Berkeley City Council.” Link: https://berkeleyca.gov/sites/default/files/city-council-meetings/2025-04-15%20Special%20Agenda%20Packet%20-%20Council%20-%20WEB.pdf
• CAL FIRE “Defensible Space” Link: https://www.fire.ca.gov/dspace
• Syphard, Brennan, and Keeley (October 14, 2014) “The role of defensible space for residential structure protection during wildfires.” International Journal of Wildland Fire. Link: https://consbio.org/wp-content/uploads/2022/05/Syphard_defensibleSpace.pdf. And http://dx.doi.org/10.1071/WF13158
• Fire Safe Marin: https://firesafemarin.org/

 

Important Disclaimer: I am not a fire preparedness professional. I am merely sharing my research, opinions, and what I find that applies to my geographic and personal situations in hopes that it will help others. Please make sure that whatever steps and advice you follow are what is best for you.

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□️□ It’s Week 4 of our #FirePrepFriday series. This week, evaluate the defensible space within 0-5 feet of your structure — also known as Zone 0. For more details, resources, tips, and links, visit my website: www.kristaleewest.com/fireprepfrid...

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— Krista West, Ph.D. (@rsfirenerd.bsky.social) April 18, 2025 at 1:59 PM