LIFE HISTORY OF LODGEPOLE PINE IN ROCKY MOUNTAINS. 



17 



This table shows how comparatively slow is the growth of lodge- 

 pole pine. One of the most striking points brought out, however, 

 is the relatively rapid growth of the dominant trees, particularly in 

 volume, amounting to approximately twice that of the average tree. 

 This indicates clearly the need for sufficient growing space if the 

 maximum development of individual trees is to be secured. 



Measurements which would permit of comparison between the rate 

 of growth in Wyoming and Colorado with that in Montana are not 

 available. Table 3, however, shows the diameter growth by decades 

 on two widely separated Forests in Wyoming, the Medicine Bow and 

 the Bighorn. In both cases the growth is typical of the average 

 sites on which the bulk of the lodgepole forests of the region are 

 found. Since in this case the measurements were collected by fol- 

 lowing the sawyers through the woods, the data secured represent the 

 growth of trees of more than the average diameter, since only the 

 larger timber was cut. Also, the stand on the Medicine Bow was 

 probably denser than on the Bighorn, which accounts for the slower 

 rate of growth upon the former. On similar sites, and with the same 

 stand density, the rate of growth for the two Forests would probably 

 be about the same. 



Table 3. — Average diameter growth of lodgepole pine on average sites on the 

 Bighorn and Medicine Bow National Forests, Wyo. 1 



Age in years. 



Bighorn 



National 

 Forest. 2 



Medicine 



Bow 

 Forest. 3 



Age in years. 



Bighorn 

 National 

 Forest .2 



Medicine 



Bow 

 Forest. s 





Diameter 

 breast high. 



Diameter 

 breast high. 



Diameter 

 breast high. 



Diameter 

 breast high. 



20 



Inches. 

 1.5 

 3.0 

 4.4 

 5.7 

 6.7 

 7.6 

 8.4 

 9.1 

 9.7 

 10.3 



Inches. 

 0.3 

 1.6 

 2.8 

 3.7 

 4.4 

 5.0 

 5.6 

 6.2 

 6.7 

 7.2 



120 



Inches. 

 10.7 

 11.1 

 11.6 

 12.1 

 12.5 

 12.8 

 13.2 

 13.5 

 13.8 



Inches. 

 7.7 



30 



130 



8.2 



40 



140 



8.6 



50 



150 



9.1 



60 



160 



9.6 



70 



170 



10.0 



so : 



180 



10.4 



90 



190 



10.8 



100 



200 



11.1 



110 











1 From Forest Service Circular 126, "Forest Tables: Lodgepole Pine." 



2 Based on decade measurements on 49 stumps of various heights, 72 to 340 years old. 

 « Based on decade measurements on 430 1-foot stumps, 159 to 300 years old. 



The growth in height of young seedlings in Montana and Colorado 

 is shown in Table 4. Figures for Montana are based on measure- 

 ments of 86 trees on the Deerlodge National Forest made to deter- 

 mine the average age required to reach various stump heights ; figures 

 for Colorado are the results of measurements of reproduction on a 

 burned area on the Arapaho National Forest. In the white-pine 

 region of Northern Idaho lodgepole makes a more rapid height 

 growth in the seedling stage than does any other species, with the 



62799°— Bull. 154—15 3 



