a0 BULLETIN 1200, U. S. DEPARTMENT OF AGRICULTURE. 
ENEMIES. 
FIRE. 
The fire situation in the Douglas-fir region of the Pacific North- 
west complicates for the timber owner and the forester the problems 
of nonproductive land and the preservation of existing merchant- 
able timber and young growth. 
FIRE RISKS. 
Effective fire protection requires a classification of the areas on 
the basis of comparative risks. In order to classify the degrees of 
fire risk, it is necessary to analyze each type of forest and the rela- 
tion of each type to all other types, so as to recognize clearly the 
areas that present the greatest risk and all the gradations of risk 
down to the least.1* As in fire insurance the extremely hazardous 
risks pay a higher rate of insurance than safer ones, so must the ex- 
tremely hazardous forest area receive more fire protection than the 
less hazardous. Classification of risks in fire insurance is based on 
the occurrence of fires in certain types of construction, on exposure, 
and on kind and degree of protection. The forest-fire risk depends 
upon the composition of the forest, the exposure, the inflammability, 
and the degree of protection given by the owner, the operator, or 
public agencies. Because of the fires that have actually occurred 
some areas would be classified as extreme risks, but many of these 
fires may have been due to lack of protection or to other controllable 
conditions. 
Inflammability is a standard that can be used as a basis for de- 
termining degree of risk. All other factors entering into the degree 
of risk vary locally and must be considered in connection with each 
area. With respect to inflammability the Douglas-fir forest region 
may be divided as follows according to the comparative degree of 
risk, the greatest risk being put first: 
. Unburned slash. 
. Open burned area, with dead weeds and some dry brush or 
branches. 
. Young stand up to 20 years old, with dead material on the 
ground and with standing snags. 
. Open stands of young growth, with weeds and grass beneath. 
. Overmature stands, with a number of snags and down logs. 
. Overmature stands, with few or no snags. 
. Dense young stands, 10,000 to 20,000 trees to the acre, 10 
years to 30 years old, with clean floor. 
8. Well-stocked young stands, 3,000 to 10,000 trees to the acre, 
10 years to 30 years old, with clean floor. 
9. Merchantable stands, 30 years old and older, with clear boles 
and clean floor. 
Unburned slash is no more inflammable than an open area with 
dry grass or weeds; but it is a more dangerous risk because it de- 
velops an uncontrollable fire with intense heat and strong drafts, 
and also makes a longer fire season. Unburned slash is a continuous 
“1 > Or (Su) bo 
13 Hofmann. J. V. A Forest Saved is a Forest Grown. West Coast Lumberman, vol. 
39, No. 465, Feb. 15. 1921. 
