COVER TYPE AND FIRE CONTROL 24 
— MEASURE OF DIFFICULTY OF CONTROL IN FIRE SUPPRESSION 
The authors’ earlier work ° with the California fire data brought 
out as perhaps the best* available index of control difficulty the 
average cost of the fires under one-fourth of an acre in extent, or 
class A fires. The cost of these small fires represents with sub- 
stantial accuracy how much work must be done in each type to con- 
struct a given length of fire line. (Table 16 and fig.9.) The highest 
ANNUAL SUPPRESSION COST PER ACRE OF TYPE. ALL FIRES. 
GENERAL RISK FIRES, 1911-1920 
GRASS —WOODLAND VILALTA 
CHAPARRAL~ BRUSH LLL eid ld 
DOUGLAS FIR MMMM Md dda dd 
Mixepconter CLL 
SUGAR PINE-FIR ZZ 
Eon Moe 0.3 0.4 
CENTS 
COSm WA" FIRES 
GENERAL RISK FIRES, ISII— CaS 
ee 
_| GRASS—WOODLAND LAI 
| CHAPARRAL ~BRUSH Page — — 
DOUGLAS FIR YQ(|_ [({CFD/D. MMM LLL — 
MIXED CONIFER Su oe 
Ren Dan Sara eee 
SUGAR PINE-FIR (ly TL LIL TL 
\ 2 an a 
DOLLARS 
PERCENTAGE OF “C” FIRES 
GENERAL RISK FIRES, I9II- Seat e 
pai lect alta is th chanel oes e 
crass-woon.ann W////YYYYL ML Lids 
CHAPARRAL- BRUSH MMMM = za Wilda 
YELLOW PINE- Ls eee 5 core ee 
MIXED CONIFER ——3 
Beary ee et eal] 
DOUGLAS FIR OOO: LLL: 
SUGAR PINE-FIR Meq@C 0 i). 
Bix Se ee 
wae 
PER SENT 
FIGURE 9.—Measures of difficulty of control, Apes righ fires, 1911-1920 
average cost per fire is in the chaparral and the lowest in the wood- 
land type. The average ($3.15) for the grass and woodland group, 
where fire-line construction is least difficult, is the lowest of all. In 
the group of nontimbered types (chaparral and brush), where fires 
are most difficult to control, the cost averages two and one-half times 
as much. For all the timber types as a group the cost 1s 58 per cent 
higher than for the grass and woodland. These figures over a pee 
: Pian a: B., and Korox, E. I. Op. cit. 
ees, a — ~ - a 
