74 BULLETIN 1294, U. S. DEPARTMENT OF, AGRICULTURE 
removal of the inferior species. On private lands, with unrestricted 
cutting, the general practice is to cull out the more valuable species 
and some of the more sound trees of inferior species, leaving as a 
nucleus for a new forest the most badly decayed and least valuable 
species and individuals. 
Silvicultural practice is difficult enough under these circumstances, 
but in reproducing areas even these difficulties are multiplied. There, 
as elsewhere, the average yearly loss from fire must be known and 
discounted in calculating for the future. Serious fires, which may 
delay growth or destroy the growing stock, can entirely disrupt a 
working plan. In merchantable forests under the present scale of 
protection the losses from fire can be stated with a fair degree of 
certainty; but for brush fields and cut-over areas the extra hazards 
have not yet been sufficiently recognized, nor has it been realized that 
especially intensive protection is necessary there. 
The problem of the brush fields is perhaps the most serious one to 
be met in fire protection in this region. The fires here are crown 
fires in effect, spreading rapidly and becoming difficult to control. 
They ordinarily result in the complete wiping out of all reproduction 
and frequently of all seed trees, thus reducing many areas from a 
timber-producing to a nontimber-producing type. The momentum 
acquired by fires in brush, too, tends to carry them with a rush into 
adjacent timber, gradually pushing back the forest and enlarging the 
brush field. Satisfactory protection of present timberlands can not 
be guaranteed while the threat of the brush fire exists; and as long 
as large fires continue to occur even very occasionally in brush fields 
and cut-over lands no effective system of silvicultural management 
of these lands is possible. 
Forest management is thus seen to be practicable only where a 
high degree of protection is put into effect. This prerequisite any 
workable theory of protection must provide for, and on brush and 
cut-over areas nothing less than fire exclusion can fulfill this require- 
ment. 
THE THEORY OF FIRE PROTECTION AS CONTROLLED BY FIRE 
DAMAGE 
Two principal theories of fire protection have been proposed (23). 
One of these, the minimum cost, or economic theory, postulates that 
the intensiveness of protection shall be such that the sum of protec- 
tion, suppression, and damage costs shall be aminimum. ‘The other 
has been termed the minimum damage theory and postulates that 
burned areas and hence damage shall be kept at an accepted, arbi- 
trary minimum. 
THE MINIMUM-COST THEORY 
The minimum-cost theory can be regarded as a clear-cut, sound, 
and workable theory only if there is a relation between intensity of 
protection and the reduction of damage, and if the facts and value 
of damage can be readily and accurately determined in advance. 
_ The first of these conditions is thoroughly proved, but the second is 
practically impossible. The true extent of damage, even in the vir- 
gin forest, is not easily determined, for many years must elapse before 
all the facts are at hand. The immediately evident losses are thus 
usually erroneously accepted as the complete and final result of fire. 
