LIFE HISTORY OF LODGEPOLE PINE IN ROCKY MOUNTAINS. 3 
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 Rocky 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 hmby. 
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 Prae 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 te 
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. Table 
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 
