LIFE HISTORY OF LODGEPOLE PINE IN ROCKY MOUNTAINS. 6 



able trees are from 8 to 14 inches in diameter breasthigh, and from 

 60 to 80 feet in height. However, trees up to 20 inches in diameter 

 and 85 feet in height are common. The largest lodgepole of record in 

 the Eocky Mountains is one on the Gunnison National Forest, Colo., 

 which is 34 inches in diameter and 100 feet tall. On the Deerlodge 

 National Forest in Montana is a tree 26 inches in diameter and 115 

 feet tall, containing six 16-foot logs and scaling approximately 1,000 

 board feet. Individuals over 30 inches in diameter have been found 

 at other places in the lodgepole region. In California there are in- 

 dividuals much larger in diameter than any mentioned, but these 

 are usually short and limby. 



Lodgepole pine seldom attains a very great age because of fire and 

 insect damage. Stands over 250 years old are uncommon, and stands 

 over 300 years very rare. The oldest stand on record is one on the 

 Beaverhead National Forest, Mont., which has attained an age of 

 about 450 years. 



As a forest tree lodgepole characteristically forms a straight, slim, 

 gradually tapering trunk with a compact, conical crown. In very 

 dense stands trees which have been crowded throughout life may 

 have extremely narrow crowns with a spread of only 3 or 4 feet and 

 occupying only from 10 to 20 per cent of the stem length. In such 

 cases the crown is usually irregular, and often appears as a mere 

 bush at the top of the tree. In stands of moderate density the 

 crown is still characteristically narrow, though more regular, and 

 occupies from one-half to one-third of the stem length. Even in 

 open-grown stands the crown seldom spreads more than from 16 to 

 20 feet, but the branches often come down nearly to the ground and 

 the taper is usually rapid. 



CLIMATIC, SOIL, AND MOISTURE REQUIREMENTS. 



The climate of the lodgepole region is comparatively dry. Tablft 

 1 gives the essential climatological facts, so far as they are available 

 from United States Weather Bureau reports. It indicates roughly 

 the precipitation requirements of the various forest types of the 

 region, data being given for stations in open country below timber 

 line, where there is too little moisture to permit natural tree growth, 

 up through the various timber types to the area above timber line. 



Lodgepole will probably grow only where the average annual 

 precipitation is 18 inches or more. As a rule the best-developed 

 stands occur where the precipitation exceeds 21 inches. It is not 

 total precipitation alone, but the amount of available moisture in the 

 soil, which determines the possibility of tree growth. This latter 



