COMPARATIVE GROWTH. 



13 



HEIGHT. 



The height growth of western yellow pine, Douglas fir, and blue 

 spruce is shown in Table 4. Both the height of the tree at each 

 decade and the periodic annual height growth are given. As in the 

 case of diameter growth, the maximum height growth of western 

 yellow pine and Douglas fir is reached at about the same time, 

 approximately at the age of 70 years. Spruce also reaches its 

 maximum height growth at an age of from 60 to 70 years, when the 

 periodic annual height amounts to 1.24 feet, or almost twice that 

 for yellow pine. 



Table 4. — Height growth of western yellow pine, Douglas fir, and blue spruce. 1 







Height. 





Periodic annual height 

 growth. 



Age. 













Pine. 



Fir. 



Spruce. 



Pine. 



Fir. 



Spruce. 



Years. 



Feet. 



Feet. 



Feet. 



Feet. 



Feet. 



Feet. 



10 



2.2 



1.3 



1.5 



0.22 



0.13 



0.15 



20 



5.0 



4.1 



4.0 



.28 



.28 



.25 



30 



9.0 



9.0 



7.0 



.40 



.49 



.30 



40 



13.6 



15.4 



14.0 



.46 



.64 



.70 



50 



19.4 



22.8 



23.0 



.58 



.74 



.90 



60 



26.0 



30.2 



34.3 



.66 



.74 



1.13 



70 



33.1 



37.7 



46.7 



.71 



.75 



1.24 



80 



40.2 



44.6 



58.0 



.71 



.69 



1.13 



90 



47.2 



51.1 



69.0 



.70 



.65 



1.10 



100 



54.0 



57.4 



78.0 



.68 



.63 



.90 



110 



60.0 



63.3 



86.0 



.60 



.59 



.80 



120 



65.5 



68.8 



92.0 



.55 



.55 



.60 



130 



70.5 



73.8 



98.0 



.50 



.50 



.60 



140 



75.1 



78.6 



104.0 



.46 



.48 



.60 



150 



79.3 



83.0 



108.0 



.42 



.44 



.40 



160 

 170 

 180 

 190 

 200 

 210 

 220 

 230 

 240 

 250 

 260 

 270 

 280 

 290 

 300 

 310 

 320 

 340 

 350 

 360 



83.1 

 86.9 

 90.0 

 93.0 

 95.9 

 98.2 

 100.4 

 102.3 

 104.1 

 105.8 

 107.2 

 108.5 

 109.6 

 110.6 

 111.3 

 111.9 

 112.4 

 112.8 

 113.4 

 113.6 



87.1 

 91.0 

 94.5 

 97.8 

 101.0 

 103.6 

 106.1 

 108.2 

 110.0 

 111.5 

 112.9 

 114.0 

 114.9 

 115.7 

 116.3 

 116.9 

 117.4 





.38 

 .38 

 .31 

 .30 

 .29 

 .23 

 .22 

 .19 

 .18 

 .17 

 .14 

 .13 

 .11 

 .10 

 .07 

 .06 

 .05 

 .04 

 .03 

 .02 



.41 

 .39 

 .35 

 .33 

 .32 

 .26 

 .25 

 .21 

 • 18. 

 .15 

 .14 

 .11 

 .09 

 .08 

 .06 

 .06 

 .05 











































■ ■ ■ 1 • 



. . , E 

















































It will be noticed from figure 2 that in early youth the spruce and 

 fir grow more slowly than the pine. This is partly explained by the 

 fact that during that period these species frequently grow under 

 cover. However, both spruce and fir finally pass the pine and lead 

 it during the remainder of life. Spruce also outgrows Douglas fir in 

 height after the age of 44 years, and at 150 years is 25 feet taller than 



1 Based on the complete stem analyses of 180 western yellow pine, 185 Douglas fir, and 135 blue spruce. 



