burning is an accepted tradition. The fire prob- Trends in frequency of forest fires reflect this 
lem has also grown steadily in the West as recrea- (fig. 22). The number of recorded fires per mil- 
tional uses, timber cutting, and other activities lion acres under protection averaged around 30 
have increased. from 1914-23. Since 1936 it has averaged about 
80 
FIRES PER MILLION 
ACRES PROTECTED 
Oo 
O 
[ 
3-year moving average 
NUMBER 
p 
Oo 
12 : 
ACREAGE BURNED PER 
| MILLION ACRES PROTECTED 
| 10 
g 
=: 
| 
| = THOUSAND SC RES 
Qs 
= 
re) 
>» 
So , , 
2 woe 
O 
1I910 I9I5 1920 1925 1930 1935 1940 1945 
YEARS 
FIGURE 22.—Trends in frequency and extent of fires on national forests, 1910-45. 
Forests and National Prosperity 79 
