16 



BULLETIN 154;, TJ. S. DEPARTMENT OF AGRICULTURE. 



the formation of a thick sod of grass that comparatively few seed- 

 lings are able to gain a foothold after that time. 



GROWTH. 



The rate of growth of lodgepole varies greatly with the quality 

 of the site and the density of the stand. Other conditions being the 

 same, the most rapid growth takes place on the best sites, but over- 

 stocking often reduces the rate of growth in such situations to a 

 point at which it is considerably less than in more normally stocked 

 stands on poorer sites. The effect upon growth of the density of the 

 stand is discussed under " Factors influencing yield." 



On account of the wide variation in lodgepole's rate of growth, it is 

 impossible to give figures which will be universally applicable. Table 

 2 shows what may be expected under certain conditions. The data 

 were obtained from 468 average trees cut by the arbitrary group 

 method in the course of a yield study on the Deerlodge Forest, con- 

 ducted in fully stocked stands on sites better than the average for 

 that Forest. Since the stands were approximately fully stocked, and 

 in some cases overstocked, the diameter growth shown is somewhat 

 less than that which may be expected in the case of trees growing in 

 stands of moderate density. On the other hand, since the sites were 

 better than the average, the height growth shown is somewhat above 

 the average. 



Table 2. — Average growth of lodgepole pine in fully stocked stands on the 

 Deerlodge National Forest. Montana, on slightly oetter than average sites, 

 oased on 468 average trees, of which 158 were dominant. 





Diameter breast 

 high. 



Height. 





Vo 



tune. 





Age in years. 



trees - : trees. 



Average 

 trees. 



Domi- 

 nant 



trees. 



Average 

 trees. 



Domi- 

 nant 

 trees. 



Average 

 trees. 



Domi- 

 nant 

 trees. 



10 



Inches. 

 0.4 

 1.2 

 2.1 

 3.0 

 3.8 

 4.5 

 5.2 

 5.8 

 6.4 

 6.9 

 7.4 

 7.9 

 8.3 

 8.7 

 9.2 

 9.6 

 10.0 

 10.4 

 10.8 



Inches. 



0.5 



1.9 



3.2 



4.4 



5.6 



6.6 



7.4 



8.2 



8.9 



9.5 



10.1 



10.7 



11.2 



11.8 



12.3 



12.8 



13.3 



13.8 



14.3 



Feet. 

 3 

 10 

 19 

 27 

 33 

 38 

 42 

 47 

 51 

 54 

 58 

 61 

 65 

 68 

 71 

 74 

 77 

 80 

 83 

 85 



Feet. 

 4 

 12 

 20 

 32 

 38 

 44 

 49 

 54 

 58 

 62 

 66 

 70 

 73 

 76 

 79 



81.5 

 84 

 86.5 

 89 

 91.5 



Board 

 feet. 1 







Board 

 feet. 1 



Cubic 

 feet* 



Cubic 

 feet? 



20 









30 







0.5 



.9 



1.5 



2.1 



3.0 



4.1 



6.2 



8.6 



10.0 



11.4 



13.5 



15.5 



18.0 



20.0 



22.0 



24.2 



26.5 



30.0 



1.0 



40 







2.5 



50 







3.9 



60 





5 



20 



35 



45 



60 



75 



90 



105 



120 



135 



150 



170 



190 



215 



240 



5.5 



70 





7.4 



80 





9.5 



90 



100 



5 



20 

 30 

 40 

 50 

 60 

 70 

 80 

 90 

 100 

 110 



m 



12.2 

 15.3 



110 



120 



130 



140 



18.5 

 23.0 

 26.0 

 30.0 



150 



34.5 



160 



39.0 



170 



44.0 



180 



49.0 



190 



54.0 



200 



11.2 



14.7 



60.0 



1 The board foot volume is based on a minimum log of 6-inch top diameter and 16-foot length, scaled by 

 the Scribner Decimal c rule. 



2 The cubic foot volume includes only the usable portion of the trunk from above the stump, usually 

 from 6 to 10 inches high, to a diameter of 3 inches in the top. 



