926 A NATIONAL PLAN FOR AMERICAN FORESTRY 



SUGAR PINE AND PONDEROSA PINE FORESTS (WITH OTHER CONIFERS) 



The sugar pine and ponderosa pine forests (with other conifers in 

 mixture) also present problems similar to those of the Douglas fir 

 forests, except that logging operations are frequently more expensive 

 and that the range of values is greater owing to the high values of 

 high-grade sugar pine and ponderosa pine lumber. Logging practice 

 has already been modified in some cases to provide for leaving a 

 residual stand, but the present practice seriously decreases the per- 

 centage of pine in the stand and in some instances removes no white 

 fir or incense cedar. Recent studies indicate that a much greater 

 volume of pine should be left in the stand, for two reasons: First, the 



FIGUKE 8. Distribution of cubic volume by diameter classes on average acre before and after cutting in 

 virgin stand of sugar pine and other conifers in California. 



pine of smaller diameters is unprofitable to log ; second, a larger growing 

 stock will provide for greater production per acre. The guiding diam- 

 eter limit indicated for selecting trees to be cut is from 36 to 44 inches. 

 Figure 8 and table 8 represent a typical stand on private lands as it 

 existed before lumbering operations, and the sound and defective 

 growing stock left after lumbering (19). The broken line shows the 

 approximate point to which it seems the first cut should have been 

 made, and the solid line shows an approximation to the stand that 

 eventually might be accepted as satisfactory permanent growing 

 stock. If the stand is cut in this way, a high stumpage rate will be 

 realized on the current cut and the lower-value diameter classes will 

 be preserved for further growth in volume, quality, and value, 



