Fuel breaks and defensible space

Defensible space, fuel breaks, and fire breaks

Defensible space: a combination of fuel breaks and landscaping around your home that is designed to prevent ignition from embers and slow down or halt fire progression.

Fuel break: an area (often a strip) where a fire will find little fuel to burn and thus move slowly, generating little heat and no embers.

Fire break: a wide fuel break, wide (the Puako fire break is 300ft wide) and bare enough to ensure that a fire will not cross under most circumstances, typically created and maintained by an entire community (but also built in emergencies by firefighting crews with large bulldozers). Paved roads in the ranch are good fuel breaks and can serve as fire breaks in moderate wind conditions.

Creating a defensible space around your home

Various groups (Firewise, Hawaii Wildfire Management Organization, other national and state organizations) have published recommendations, differing in small details, but agreeing on all general principles; see [various URLs]. The main points are:

a) Keep flammable vegetation (anything higher than a few inches) well away (30-100 ft is the standard recommendation) from your home, in all directions. Prune trees that overhang your roof and remove or severely prune bushes close to walls or windows.

b) Maintain that cleared space: keep any trees trimmed and bushes pruned, mow any low vegetation, and remove all dead vegetation and clippings.

c) Where removing or severely trimming vegetation close to your home is not doable, protect that area by setting up a fuel break around it.

Setting up a fuel break

A fuel break is a wide strip (at least 15ft) where you have removed most of the fuel, by cutting all vegetation down to a few inches, removing all dead and freshly cut vegetation, and pruning any tree branches arching over the area back to at least 10ft off the ground.

Weed cutters and rakes are the usual tools for maintaining fuel breaks on rough ground.