Built to Burn - Design with the Desert: Conservation and Sustainable Development - page 217

(a) (b)

FIGURE 11.6
Burned houses (a and b) at Summerhaven, Arizona, showing structures completely consumed while surround-
ing (dense) forest is unburned; the fires spread along the surface, or between houses, not through the coniferous
canopy. (From Cohen, J.D., An examination of the Summerhaven, Arizona home destruction related to the local
wildland fire behavior during the June 2003 Aspen fire, Intermountain Fire Sciences Laboratory, unpublished
repor t, 20 03.)

landscapes. Investigations into the Aspen fire that gnawed into Summerhaven on the top
of Mt. Lemmon in Arizona suggest that most conifer crown burning was the result of igni-
tion from burning houses, not vice versa, while between houses, fire spread on surface lit-
ter (Figure 11.6). In wildlands, the zone of protection must extend outward, an aura known
as defensible space. This near-landscaping need not be stripped, only sculpted to dampen
fire's ability to creep into, radiate toward, or hurl embers at the house. All parties agree
that this is properly the duty of a homeowner, not only to himself but to his neighbors. The
shouting begins when defensible space is expanded to the community itself, particularly
when a hamlet abuts against public land because it effectively extends the influence of pri-
vate landholdings into the public domain and becomes subject to national politics. 8
One proposed solution is to adopt fuelbreaks as a kind of fire levee that can keep the
flow of wildfire from overspilling into communities. On this subject, the United States
has considerable experience, with mixed lessons for community protection. The core rea-
son for ambiguity is that large fires are large events; they can swallow whole swathes of
landscapes. Slivers of thinned fuels—the fuelbreak as moat—will not halt the big fire that
most threatens a reserve or hamlet. Fuelbreaks work best when they are built into the
design of landscapes, not retrofitted. They function nicely in pine or teak plantations, for
example, when constructed as part of the original layout. They work poorly when imposed
on mature forests. They are, moreover, temporary features. They reduce an immediate
hazard, but cannot hold forever. Broad corridors (and roads) slashed through Oregon's
Tillamook Burn helped break the continuity of fire-killed snags, but only until the cycle of
reburns ceased and the mountains were replanted. Plowed and fired fuelbreaks through
the Nebraska Sandhills helped shatter the near-annual flow of prairie fires, but overgrew
after the pine plantations ripened. Fuelbreaks require maintenance, and once the crisis has
passed, reluctance at the expense and labor of annually weeding, cutting, and burning
overwhelms the project. (Clearing fuelbreaks was one of the early uses for which Agent
Orange was developed.) Fuelbreaks are, that is, transient devices that work best at the
onset of a project for lands of considerable value. 5