COMPAEATIVE GEOWTH. 



15 



Table 5. — Volume growth of western yellow pine, Douglas fir, and blue spruce. 







Age. 





Time required to 



grow 1 inch in 



diameter. 



Number of 16- 

 foot logs. 







Volume. 







^2 











































o5 







03 





















o 







o 





















c3 bo 



03 



.u 



g 



03 



Sh' 



B 



03 

 Pi 



•fa 



a 





§ 





u 





3 



Q2 



Ph 



fe 



CO 



Ph 



£ 



co 



Ph 



Ph 



CO 





Ph 





s 





CO 























Bd. 





Bd. 





Bd. 





Ins. 



Yrs. 



Yrs. 



Yrs. 



Yrs. 



Yrs. 



Yrs. 









ft. 



Cu.ft.i 



ft. 



Cu.ft. 



ft. 



Cu.ft. 



12 

 13 



100 

 107 



99 

 105 



69 



72 









1.2 



1.5 



1.1 

 1.4 



1.0 

 1.0 



40 

 50 



15.32 

 19.60 



30 

 50 



14.98 



18.88 



■ 30 

 30 



13.80 

 16.12 



7 



6 



3 



14 



114 



111 



76 



7 



6 



4 



2.0 



1.7 



1.0 



90 



24.63 



80 



23.07 



30 



19.50 



15 



122 



117 



81 



8 



6 



5 



2.2 



2.0 



1.3 



120 



31.08 



100 



27.83 



50 



23.87 



16 



129 



123 



86 



7 



6 



5 



2.5 



2.2 



1.5 



150 



37.57 



120 



32.78 



70 



28.77 



17 



136 



129 



91 



7 



6 



5 



2.8 



2.5 



1.8 



190 



44.66 



150 



38.14 



90 



33.76 



18 



144 



135 



97 



8 



6 



6 



3.1 



2.8 



2.0 



220 



53.02 



180 



44.14 



110 



40.13 



19 



152 



141 



104 



8 



6 



7 



3.5 



3.0 



2.4 



310 



61.87 



190 



50.37 



150 



48.00 



20 



160 



147 



111 



8 



6 



7 



3.7 



3.2 



3.0 



360 



71.78 



240 



57.10 



200 



56.19 



21 



168 



153 



120 



8 



6 



9 



4.0 



3.4 



3.2 



430 



82.24 



310 



63.11 



260 



66.72 



22 



176 



160 



130 



8 



i 



10 



4.1 



3.6 



3.6 



500 



92.86 



340 



71.62 



360 



77.98 



23 



184 



166 



142 



8 



6 



12 



4.3 



3.8 



4.0 



580 



103. 91 



380 



79. 35 



420 



89.85 



24 

 25 

 26 

 27 

 28 

 29 

 30 

 31 

 32 

 33 

 34 



193 

 202 

 211 

 220 

 230 

 241 

 252 

 264 

 277 

 . 292 

 308 



173 

 180 

 187 

 194 

 202 

 210 

 219 

 229 

 239 

 249 

 260 





9 

 9 

 9 

 9 

 10 

 11 

 11 

 12 

 13 

 15 

 16 



7 



7 



8 



8 



8 



9 



10 



10 



11 



11 







4.5 

 4.6 

 4.9 

 5.0 

 5.1 

 5.3 

 5.5 

 5.7 

 5.8 

 6.0 

 6.1 



4.0 

 4.1 

 4.2 

 4.4 

 4.6 

 4.8 

 5.0 

 5.1 

 5.3 

 5.5 

 5.6 





610 



710 



810 



920 



1,040 



1,150 



1,250 



1,420 



1,530 



1,720 



1,880 



117.00 



130. 44 



143. 45 

 158.16 

 173. 66 

 189. 94 

 206. 76 

 225. 25 

 241. 19 

 266. 88 

 288. 68 



430 



500 



560 



640 



720 



800 



900 



1,020 



1,130 



1,220 



1,370 



88.55 

 97.98 

 107. 82 

 117.88 

 129. 67 

 141.77 

 155. 81 

 171.74 

 187. 99 

 204. 48 

 222. 85 













































35 

 36 



326 



346 



272 



285 





18 

 20 



12 

 13 





6.2 



6.4 



5.8 

 6.0 





2,060 

 2,250 



312.18 

 336. 13 



1,480 

 1,680 



242. 47 

 263.04 











37 

 38 





298 

 312 







13 

 13 







6.1 

 6.2 









1,840 

 1,960 



282. 82 

 302. 84 











































1 Each log is cubed according to Smalian's formula. The top above a point 8 inches in diameter is cubed 

 as a cone and the stump as a cylinder. 



To reach a diameter of 12 inches, western yellow pine and Douglas 

 fir require 100 and 99 years, respectively, while spruce requires only 

 69 years. At 110 years the spruce is still making a good growth, 

 but soon after this it falls off rather rapidly, and maturity is prob- 

 ably reached not long after it is 150 years old. Further proof of this 

 is found in a comparison of the number of years required to increase 

 1 inch in diameter. At 12 inches spruce increases an inch in diam- 

 eter in 3 years, while it takes pine and fir 7 and 6 years, respectively. 

 But with an increase in age in spruce there is a corresponding increase 

 in the length of time required to grow 1 inch, while for pine and fir 

 this period remains practically the same up to 180 years. 



In comparing the number of 16-foot logs (top diameter of 8 inches) 

 which the different species will cut at a given diameter, it is found 

 that western yellow pine leads both fir and spruce, in spite of the 

 fact that the latter species makes a faster growth in both diameter 

 and height. The explanation lies in the difference in form of bole 

 and thickness of bark. Although spruce has a thin bark, the stem 

 tapers very rapidly and quite evenly throughout its entire length. 

 Occasionally it is swell-butted. The bark of Douglas fir is much 

 thicker than that of either spruce or pine, and, like spruce, the bole 

 does not ''fill out," but has a considerable taper, even in old age. In 



