BULLETIN OF THE 



No. 154 



Contribution from the Forest Service, Henry S. Graves, Forester 

 January 14, 1915. 



THE LIFE HISTORY OF LODGEPOLE PINE IN THE 

 ROCKY MOUNTAINS. 



By D. T. Mason, Assistant District Forester, District 1. 

 GEOGRAPHIC DISTRIBUTION AND ALTITUDINAL RANGE. 



Lodgepole pine (Pinus contorta Loudon) is one of the most widely 

 distributed western conifers. Its botanical range, shown in figure 1, 

 extends from the Yukon Territory southward through the Cas- 

 cade, Sierra Nevada, and San Jacinto Mountains to northern Lower 

 California, and through the main range of the Rocky Mountains 

 to northern New Mexico. Its commercial range, however, is much 

 more restricted. At present lodgepole is being lumbered exten- 

 sively only in Montana, Wyoming, Colorado, and the Uinta Moun- 

 tains in northeastern Utah. Large areas also occur in Idaho, Wash- 

 ington, Oregon, and California, but in these regions the tree is 

 rendered less important commercially by the presence of other and 

 more valuable timber trees. 



The "lodgepole region" — that in which lodgepole is the preemi- 

 nently important species — is mountainous, frequently interrupted by 

 broad, open valleys, or plains, partly fertile and devoted to farming, 

 and in part suitable only for grazing. The forests, as a rule, are con- 

 fined to the mountains. 



The altitudinal range of lodgepole pine in the Rocky Mountains 

 decreases from south to north. In Colorado and southern Wyoming 

 the tree is found at altitudes ranging from 7,000 feet to timber line, 

 or 11,500 feet ; in northern Wyoming at from 6,000 to 10,500 feet ; and 

 in southwestern and central Montana at from 4,500 to 9,000 feet. As 

 a rule, however, it forms commercial stands only within an altitudinal 

 belt from 2,000 to 2,500 feet in width. In Colorado the best stands 

 are usually between 7,500 and 9,500 feet; in Wyoming between 7,000 

 and 9,000 feet; and in southwestern and central Montana between 

 6,000 and 8,500 feet. In the more humid northwestern portion of 

 Montana, outside of the main lodgepole region, the species grows at 

 62799°— 15 1 



