Natural wildfires have been increasing in frequency and severity in recent years. Land owners can take concrete steps to protect themselves, their family, and their property by following purposeful design choices. This puts the power in your hands. No matter the global climate or political leadership, you can improve the safety and security of your site as soon as you’d like.
A fire needs three things
Fuel is the only one we can really control. That’s why we see everyone everywhere suggesting that land managers remove any backlog of fuel which is already building up in the natural environment.
Beware any of the edges or corners of your building; anywhere wind and wind-born particulate can build-up or swirl about. You see, it’s actually embers drifting on a breeze from a far-off fire which contribute to the most number of homes lost. If you look at a fire from afar, then of course there is a burning front which advances towards fresh material. But if you zoom in, that burning edge is disproportionately advanced by the ashes, embers, and sparks blown forward of the main fire. If they can land and heat the right spot, they start the blaze which speeds the wildfire.
When designing your house for fire resistance, look to minimize or protect:
You can see from these points that keeping the area immediate surrounding your house is incredibly important.
Maintain a 5’ barrier which keeps vegetation separate from the house. Measure these five feet at least from the foundation, but preferably from the edge or dripline of the building’s eaves.
First, as a classic tenet of permaculture, assess the site’s sectors. In particular, in this case, your fire threat and wind sectors. Then, create a design in response.
Another overlap with permaculture planning is breaking the site into zones. In this case, we have three zones with standard/minimum distances to direct landscape maintenance. There is an optional fourth zone which could apply to a large enough site (>100’ from any buildings) and if the land managers wanted to expend the effort to maintain the area.
Mulch can burn as well. Keep it away from your house as well, make fire breaks in your mulch as well. Bark mulch is more likely to smolder, slower than needle mulch (really this is just a recommendation for greater particle size and density, basic rules of making something harder to burn/less combustible).
Bias hardscapes towards the direction of the most likely fire danger. This will provide the least combustible materials for the most likely direction of incoming sparks. Make them work for it and have to travel just that much further if they want to try to light your house on fire!
Irrigated grass walkways or hardscaping can be use to isolate islands of plants while providing fuel breaks across the landscape.
Emergency sprinklers will be worth every cent spent if they are ever activated to save your house from a wildfire. This could mean adding additional sprinklers along your landscape’s perimeter. These will, of course, be on a separate circuit and always off unless and until needed. A last, but effective, line of defense is to install another emergency circuit of sprinklers on any structure’s roof! And now, one final detail: a good design will ensure these emergency sprinkler circuits are gravity-fed with emergency water stored high on the landscape. After all, if the emergency sprinklers are needed, then it’s a disaster scenario and we don’t want to count on anything and have back-ups for everything.
You can also use water reservoirs high on the landscape to flood a region below. Maybe it holds enough water to fill a an entire pasture between you and the fire with three inches of water. Maybe it rushes down to fill a modern moat, a berm or swale designed not for percolation and groundwater recharge but for simply being a wide swath of water as a hard barrier for any advancing line of fire.
All this talk of reservoirs demands I point out that concrete reservoirs are less damaged by fire than many other materials. And when you’re building for these scenarios, try to put your emergency water pipes underground where they’ll be protected so they can do their job of protecting your landscape!
Spacing between plantings needs to increase when: there is a steeper slope, taller vegetation, and/or when in a more fire prone site.
| Slope severity | Canopy height for distance between plant groupings |
| No slop | 2x |
| 20-40% | 4x |
| 40%+ | 6x |
Fire resistance features:
All plants can burn.
Plant fire-resistant ones which are known to survive fires and regrow afterwards (always planning for the worst).
Minimize maintenance so that it doesn’t accumulate fuel, especially if you stop maintaining the plant.
Look for plants with high overall moisture content in their biomass.
See both primary recommendation and immediate area both for reminders not to plant so close to your house! Five feet away form your house, minimum!
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This is all the basic information you need to plan a robust landscape design that can not only resprout after a wildfire but also protect your property during the wildfire itself!
If you’d like to learn more about this topic, I encourage you to look for resources from both California and Australia; both places really pushing the frontier of fire research and fire mitigation education work.
If you would like to let an expert landscape designer take care of this concern for you, then reach out to me right now! The next fire could be right behind the next hill. I’ve seen it happen; I’ve evacuated from those fires, I’ve traveled those ash-covered & post-apocalyptic-looking landscapes.
CA Fire Sci. Consortium (2016): https://www.youtube.com/watch?v=DJfzAdsk8H8
UC – Ag and natural resources: https://ucanr.edu/sites/forestry/Wildfire/
Australian Institute of Architects – site planning & design for bushfire: https://www.architecture.com.au/wp-content/uploads/Acumen_Site-planning-and-design-for-bushfire_Australian-Institute-of-Architects.pdf
