72 BULLETIN 12%, U. S. DEPARTMENT OF AGRICULTURE 
The discussion of the effect of fire would, however, be incomplete. if 
it were confined to the present physical condition of the forest. We 
are at the point in the silvical sary economic history of this country 
where the effort to preserve forest land for future forests and to ob- 
tain the highest permanent yield from such forest areas is of prime 
importance in the Nation’s welfare. The réle of fire is consequently 
nowhere more significant than in the sphere of forest management, 
or in determining what can and what can not be done in managing 
our forest properties more intensively in the future. 
EFFECTS ON LOGGING COSTS 
Loss from fire must always be considered in terms of both quality 
reduction and quantity reduction. Both these forms of attrition 
affect the merchantability of timber and the cost of logging. 
Quality reduction is effected in the destruction of the largest and 
- most valuable individual trees, and in direct loss of the best quality 
of wood in standing trees. One of the principal agencies of this form 
of loss is the fire scar, which destroys the wood of the butt and leads 
to burning down, windfall, and the entrance of insects and fungi. 
In the virgin pine forest, the trend of all fire damage, save heat kill- 
ing and the rare crown fire, is to eliminate the oldest, the largest, 
and therefore the most valuable individuals from the stand. 
Quantity reduction, or the work of attrition in thinning out the 
maturing stand, is a direct tax on what in logging costs is called the 
fixed investment. In modern logging the fixed investment is heavy, 
especially in railroad construction, and must be charged against the 
crop or the product derived from the specific area. If a body of 
timber is reduced in volume by even 10 per cent, the construction 
charge for each thousand board feet is correspondingly increased for 
the remaining 90 per cent. The increase in yarding costs brought 
about by quantity reduction is, within small limits, of minor moment, 
since it proceeds pepe from the increased frequency with which 
donkey engines must be moved, an operation that ordinarily costs 
not more than 10 cents a thousand board feet cut. On poor sites, 
however, and often such as barely justify logging at all, a loss of even 
1,000 or 2,000 feet an acre may remove the stand entirely from the 
exploitable class. How this is worked out in practice is shown 
below. 
In the first area, representing 300,000,000 board feet of annual 
cut, located on the west slope of the Sierras, in a mixed conifer type, 
the average stand per acre is reckoned at 28,000 board feet. Rail- 
road cost per thousand board feet is $1.80; yarding cost, which 
involves moving of outfits from landing to landing, is $0.51 per 
thousand; a total of $2.31 per cueisade board feet. Both these 
factors of cost are affected by density of stand. To what extent 
the total cost is affected by reduction in stand per acre is apparent 
in the following figures: 
Reduction of 500 board feet increases cost $0.04 per 1,000, or $1.12 per acre. 
Reduction of 1,000 board feet increases cost $0.085 per 1,000, or $2.38 per acre. 
Reduction of 1,500 board feet increases cost $0.13 per 1,000, or $3.64 per acre. 
Reduction of 2,000 board feet increases cost $0.18 per 1,000, or $5.04 per acre. 
Similarly, on an area on the east slope of the Sierras, in the western 
yellow pine type, representing an annual cut of 265,000,000 board feet, 
