1442 A NATIONAL PLAN FOR AMERICAN FORESTRY 



out by overgrazing. Commercial cutting is not ordinarily as close 

 as in most of the major types previously discussed. High-power 

 machinery is used in some of the heaviest stands, but animal or 

 tractor logging are far more common. Although the fire hazard is 

 ever present, conflagrations, except in slash, are not common, and 

 the control of fire, both before and after logging, is not exceedingly 

 difficult. 



The measures necessary to insure continued productivity in this 

 type, in addition to the fire protection described in an earlier section, 

 may be briefed as follows: 



CUTTING 



No trees should be cut of a size below the economic limit set by 

 careful studies of the relative profitableness of large and small trees 

 and of the probable future returns from those of small present value. 

 Sound business practice indicates a minimum limit for saw timber 

 between 15 and 20 inches in most parts of the type, but in a few local- 

 ities and for products smaller than logs the limit may be less. Diam- 

 eter-limit cutting coincides fairly well with good silviculture in this 

 type. Each tract should be studied to determine the economic 

 limitations for cutting, bearing in mind the growth and prospective 

 value of the trees that might be left, in contrast with their present 

 value. The inferior species, where present, would be cut very lightly. 

 Such a cutting for saw logs only will leave a forest cover, the nucleus 

 of a future cut, and enough seed-producers gradually to fill out the 

 stand, on the great majority of areas. In Arizona, New Mexico, and 

 adjacent territory, where advance reproduction is absent and thrifty 

 trees below 21 inches diameter breast high are insufficient it will 

 occasionally be necessary to leave 800 to 1,000 board feet in seed 

 trees, per acre. 



LOGGING 



Because of the supreme need to preserve all young growth and 

 unmerchantable trees against damage, all forms of logging should 

 be very carefully regulated to this end. Even animal and tractor 

 logging may result in unnecessary swamping out of roads, turning 

 points, etc., and in damaging standing trees. 



SLASH DISPOSAL 



Slash disposal is necessary on a part only of each cutting area, as 

 described under the same heading in the sugar pine-ponderosa pine 

 type. 



OTHER MEASURES 



Similarly, better-than-average protection should be given cut-over 

 areas. See the previous type. 



Overgrazing should be guarded against. Moderate grazing, on 

 the other hand, is a double asset in logged-ofF pine land; it helps the 

 owner to defray the cost of carrying the land for continuous forest 

 production, and tends to keep down the fire hazard of grass and 

 brush, as well as competition of this vegetation with seedling growth. 

 Experience has shown, as earlier emphasized, that a future crop of 

 ponderosa pine depends even more on reproduction established before 

 cutting than on that secured after cutting. This fact makes necessary 



