32 BULLETIN 1495, U. S. DEPARTMENT OF AGRICULTURE 
of years, besides expressing the average differences in labor required 
to suppress fire of a given;,size, indicate also the relative size of crew 
required to construct a given length of line in a given time. Thus 
for brush and chaparral fires, a crew two and one-half times as large 
is required as for woodland and grass fires. Moreover, since the cost 
measures the amount of fuel to be removed in line construction and 
the amount of fuel present is an indication of the severity of the fire, 
these costs have a further significance as indicating the inherent 
hazards. 
Within the timber belt itself the differences between types are not 
nearly so great as between the major groups of types. (Fig. 10.) 
Pure fir, at $4.15 is indicated as the easiest timber type in which to 
control fire, and Douglas fir, at $5.90, as the most difficult. Probably 
the high figure for Douglas fir is affected by the location of most of 
GRASS LLL 
WOODLAND YJOV'\l'l. 
BRUSH HHHHHHHYVCTTE€¥M@@ECTX€XZTZ@000. 
iar: rear eee] 
YELLOW PINE YWYffYY@M {j?{MCM@AaAT™T@CMEEY 
Fey Pa eee ES or vba ee) 
DOUGLAS FIR YY ff MMH 
Eas Fah ie Ee) 
MIXED CONIFER WYYHHHY YY WY GEE. 
SUGAR PINE-FIR fff Jw: 
Ca Se ee a | 
FIR WVMMCXZ7=0”M!’™!™’l 
te) ' 2 3 4 
5 6 
DOLLARS 
FIGURE 10.—Average cost per A fire, by types, all causes, 1911-1920 
the type area in the northern group of forests, where the difficulty 
and hence cost of reaching fires averages greater than in other parts 
of the region. 
_ COST OF SUPPRESSION 
Average cost per fire for ail general-risk fires (Table 17) varies in 
much the same way between types as the cost of class A fires. Of 
the timber types, fir has the lowest average cost and Douglas fir the 
highest. Chaparral has the highest cost of all, followed by brush 
and woodland, all higher than the timber types. In the major 
type groups, the average cost of brush and chaparral fires is nearly 
double that in the western yellow pine and mixed conifer types. 
The cost in the grass and woodland types is intermediate between 
all timber and the brush values. 
The total cost of suppressing all fires in a type is of course measured 
both by the cost of the average fire and by the number of fires per 
100,000 acres in the group. Combining the two as ‘Cost per acre per 
year’’ produces an expression of suppression cost by types. Within 
the timber types, the cost is lowest in pure fir and highest in Douglas 
fir, while costs in western yellow pine and mixed conifer are identical. 
The highest cost of all is in the chaparral and the lowest in the grass 
type. 
