between cuttings the immediate margin of profit and the subsequent 

 growth. The basis for choosing the cut and leave trees, therefore, 

 was somewhat different than if regeneration had been the foremost 

 goalo Each resulted in removing different amounts of sawtimber and 

 will be called in this report heavy, medium, and light cuttings, re- 

 spectively. 



The heavy cutting remioved virtuelly all ponderosa pine and Douglas 

 fir trees of the then minimum morchantable diameter of 14 inches, and 

 larger. On the medium cutting, vigorous, high-quality ponderosa pine 

 having the greatest growth potential were reserved. The light cutting 

 removed only high-quality ponderosa pines 14 inches in diameter and 

 larger. Furthermore, in this cutting only those logs whose lum.ber 

 selling value exceeded production costs were removed from the woods. 

 Stand volumes before and after cutting and the vol'om.e cut by eacn 

 intensity are shown in table 1. 



Following cutting, all trees 4 inches d.b.h. and larger were tagge 

 and measured at 5-year intervals. Trees subsequently reaching the 4- 

 inch diameter class were tagged and measured in 1947 and 1952. 



RESULTS 

 Growth of Residual Stands 



Board-foot volume accrual on the 120- to 220"j''ear-old sawtimber 

 reserve was similar to that repor':.ed from other ponderosa pine studies 

 in western Montana. ^»^ / Periodic annual gro-rbh on reserve trees in- 

 creased substantially in the s'jcor.d P-year period after cutting and 

 tended to culminate during the third or fourth period (figure :.)„ 



The 20-year increment of each re'^er^re stand varied directly with 

 residual volume. On the heavy cutting gross growth totaled 954 board 

 feet on a reserve of 2,013; on the medium cutting, 1,948 on a reserve 

 of 4,150; and on the light cutting, 2,352 on a reserve of 10,004 board 

 feet. Percentage-wise, gross growth on the light cutting was 24 per- 

 cent of the reserve volume for the '^O-year period or about one-half of 

 the percentage increases on the heavy and medium cuttings. These per- 

 centage differences reflect the multiple effects of reserve voliome, 

 tree size, age, vigor, and growing space. 



3/ Roe, Arthur L. Whet is the :"ight cutting cycle for ponderosa 

 pine? North. Rocky Mtn. Forest and Range Sxpt. Sta. Res. Note 57, 3 

 pp. 1947. 



4/ Roe, Arthur L. Orowth of selectively out ponderosa pine stands 

 in the Upper Columbia Basin. Agr. Handb„ 39, 28 pp. 1952. 



