The typical fire break is a strip of barren land that is equal to or slightly wider than the vegetation beyond the break. A section of land totally denuded of anything that might burn. On some properties this may eat up LOTS of valuable land and is quite wasteful to boot.
How does one work out fire protection in a permaculture situation.
I grew up in wild fire country, and worked for County Forestry in my teens.
Most of the fire breaks I'm familiar with are in So Cal, where most of the vegetation is chaparral.
Our fire breaks were usually at the crests of hills, and a minimum width of about 40 feet.
You cannot stop one of those fires going up a hill. The object is to keep it from going down the other side.
Timber country would need a much wider break.
If you have 100' trees, the break must be wider than 100', lest one fall across the break.
As far as dealing with wild fires on a permies homestead, I think that a lot of the common precautions taken in other fire areas would be the same.
* Appropriate roofing materials: as pretty as they are, cedar shingles are not suitable for fire prone areas.
* Large, overhanging eaves, while great for catching rainwater, are fire/heat traps.
* Control vegetation close to the house. No tree limbs overhanging the roof, or bushes under the eaves.
* A pond near the house may save the house. You will need a goodpump - volume and pressure.
For somebody living on a slope in fire country, I would suggest planting low lying crops down slope from the house, and the larger trees up the hill from the house. With the same vegetation, a fire will spread about 16x faster up a slope than on the level. Burning down hill is much slower, and controllable. As a fire races up the hill, it creates its own wind, a 'fire storm' that can easily generate winds 40-60 mph. That's why we seldom fought a fire going up a hill. We would go to the top, and widen the break before it got there, or if it was already going down the other side, we would get a few hundred feet ahead of it and try to cut new breaks before it got to us. Sometimes it worked, sometimes it didn't.
Also, keep your plants well watered before and during fire season. Vibrant green plants will sizzle & pop. Dried out plants will explode!
An irrigated vegetable garden can be a fire break. A pond, a road, a lawn, patio, a greywater wetland system, an irrigated orchard, a cistern. The point is to identify the fire sector (the direction most likely for a fire to come from). Fire travels up slope, with prevailing winds, through fire prone vegetation, on hotter Southern and Western slopes. Then stack many elements in that sector that would break the path of fire, like those mentioned. Then by design, you have a fire break, even though it's not comprised of cleared barren land without multi-functions. Also, water storage cisterns or ponds are placed where they can be emptied by gravity in the path of an oncoming fire. The electricity goes out early on in a region-wide fire, so water dispursing strategies need to be non-electric grid.
these guys are around, and have trailers they go out and spray the multimillion dollar homes.
You can buy some Phoschek, if you have gaps on your deck, to help protect the house too.
You set it up like a drip system , and use stored compressed air to blow it out micro sprinklers when a fire is coming
We just bought some old swedish manual fire pumps, and keep a 5 gal of it , just in case.
old fire sprinklers were set up super-simple, with a wax plug in a jar of water hung upside-down, and designed to spray out once the wax melted. Note there have been some improvements since then. But I would think some wooden rainbarrels around a house could be an asset, if kept full.
Here's a site that has good general data and goals. Integrating fire gaps and radiant heat barriers into earthworks, windbreaks, and other planting designs, and using your zone and sector analysis to emphasize relevant placement of things for the greatest effect / lowest risk, you can combine permaculture and fire-defensibility.
My first step today is going to be to go pull some landscaping plastic out of the pond area, so we have an escape place. And to get the re-vegetation started; I don't like the landscaping plastic, but may split the difference and leave half the plastic with slits cut in it to help the plants start in moist conditions, the other half comes out now while the water's low so we have a place to go without burning plastic in the event of a big one.