50 BULLETIN 871, U. S. DEPARTMENT OF AGRICULTURE. 



On the National Forests a great deal can be accomplished in the 

 way of control of mechanical injuries resulting in wounds through 

 which the dry-rot fungus can enter. As has been shown, fire is by 

 far the most important factor in promoting dry-rot, with knots, the 

 nearest competitor, of relatively far less importance both in regard 

 to the number and seriousness of resulting infections. 



Fire can be, in a great measure, directly controlled. The ever- 

 increasing efficiency of the fire-protection methods on the National 

 Forests, with the continual reduction in the number of damaging 

 fires, speaks for itself. Certain private holdings are also protected 

 from fire, either incidentally by falling within the boundaries of a 

 National Forest or through a protection system handled on a coop- 

 erative basis by the United States Forest Service. Knots, of course, 

 can not be controlled. Natural pruning, with the continual produc- 

 tion of dead branches, which later break off, is inevitable in any 

 forest. However, it may be expected that infections through this 

 source will become increasingly fewer as time goes on, in proportion 

 to the reduction in the number of fire-wounded trees. All other 

 factors, whether controllable 'or uncontrollable, and this includes frost 

 and hghtning, are of so little importance that they may be neglected 

 in any consideration of mechanical injuries in the future stand. 



But fire protection works for the future welfare of the stand alone. 

 It can not affect the huge number of individuals in the forest with 

 healed or open wounds through which dry-rot has already entered 

 or those uninfected individuals with open wounds still exposing them 

 to attack by heartwood-destroying fungi; nor can it have any influ- 

 ence on all the other injured, diseased, or distorted members of the for- 

 est community. These have no place in the stand, are in most cases a 

 direct menace to the sound trees, and should be removed as soon as 

 possible. Unfortunately, we have not been able to. attain the highly 

 desirable intensive practice of eradicating such undesirable individuals 

 by means of improvement thinnings applied at will wherever needed 

 in the forest. 



Under present conditions this can only be done in the main through 

 timber sales, with free-use permits playing a limited part. But the 

 Government is far from able to sell the timber where cutting is most 

 needed from a silvicultural point of view. Economic factors, espe- 

 cially transportation, and in some cases the degree of soundness of 

 the stand play the chief role in determining the exact location of a 

 sale area. In fact, a mature or overmature stand badly in need of 

 cutting may have to be left untouched, owing to the refusal of pros- 

 pective purchasers to handle the high representation of inferior 

 species. 



In the case of incense cedar, this prejudice on the part of the lum- 

 berman does not arise from any inherent qualities or characteristics 



