1440 A NATIONAL PLAN FOR AMERICAN FORESTRY 



materially reduce the damage to seed trees and destruction of young 

 growth once prevalent in the region. 



The large quantity of slash and debris produced when stands yield- 

 ing 15,000 to 60,000 board feet per acre are cut, added to advance 

 reproduction and brush present before logging, gives cut-over areas 

 in any type possibilities of fires far more intense, more damaging, 

 and more difficult to combat than in the virgin forest. The minimum 

 effect of slash fires is the destruction of advance reproduction and 

 death of some immature trees. Such fires, moreover, do not com- 

 pletely consume the slash, and a fire hazard, which the burn aims to 

 reduce, remains. The rapid invasion of worthless brush is also aided 

 thereby and subsequent protection is made more difficult. 



The following measures are necessary to stop forest devastation : 



SELECTION CUTTING 



In the sugar-ponderosa pine type an approach to economic selection 

 has unintentionally come about at the present time because of a 

 greatly depressed market. This has been a favorable factor in pre- 

 serving forest productivity. As log values increase, however, under 

 more favorable market conditions the tendency to cut to lower 

 limits will again become evident, particularly affecting the valuable 

 sugar pine and ponderosa pine. Under the principles of economic 

 selection, cutting should be held strictly to trees that can be logged and 

 milled at a profit. In the better stands on the west slope of the 

 Sierras it is unprofitable under normal market conditions to cut pine 

 below 24 inches diameter breast high. In east slope stands the lower 

 limit of profit is probably 18 inches. For inferior species, such as 

 white fir, the limit is of course much higher. Although the leaving of 

 poorer species to compete with good is not desirable, it keeps the land 

 productive by guaranteeing a merchantable second crop of some sort. 



SEED TREES 



Wherever in ponderosa pine stands cutting to the economic limit 

 would not leave standing an average of at least four trees of ample 

 seed-bearing size to the acre their equivalent in larger trees should be 

 reserved from cutting. Ponderosa pines having the largest cone pro- 

 duction per unit of merchantable volume are generally 18 to 20 inches 

 in diameter, and this relative production is about twice as high as for 

 30-inch trees. From 1,000 to 1,500 board feet per acre in well dis- 

 tributed trees having good, vigorous crowns will usually be sufficient. 



LOGGING 



Logging should be carefully conducted so as to destroy no more 

 advance reproduction than is absolutely necessary. Horse or cater- 

 pillar logging should be used on all ground adapted to it. High 

 leads and the use of high-speed machines should be discontinued 

 and other forms of high-power logging carefully regulated. 



SLASH DISPOSAL 



The slash disposal methods should be elastic enough to meet local 

 variations in fire hazard, character of forest, and topography. In 

 general a method of partial disposal is recommended, by which slash 



