15 



Count) r ; Wash., is excellent for the latitude and rainfall. The west 

 slope of the Rocky Mountains must have a favorable effect on the 

 moisture conditions there. The west slopes of the Sierras in central 

 and northern California show a magnificent growth, which is auspi- 

 cious for forest management. The rainfall there is heaviest in the 

 entire range of }^ellow pine. Soil and other conditions no doubt have 

 their influence on growth, but the extent is not yet ascertainable. In 

 all measurements, and especially in diameter growth, it must be borne 

 in mind that individual trees often greatly exceed the average. In 

 the Black Hills it takes one hundred and twenty years for the average 

 tree to reach the merchantable size of 10.5 inches, yet some individual 

 trees reach that diameter in a much shorter time. 







Table 12. — .Diameter g 



"owth by general 



regions 







Nemo, Black Hills National 



Flathead and Missoula 



Pagosa Junction, Archu- 



Age. 



Forest, South Dakota. 



counties, Mont. 



leta County, Colo. 



Diam- 





Diam- 





Diam- 







eter 

 breast- 



Basis. 



eter 

 breast- 



Basis. 



eter 

 breast- 



Basis. 





high. 





high. 





high. 





Tears. 

 10 



Inches. 





Inches. 

 I 



0.8 





Inches. 

 ----- 





20 



1.0 



30 



1.9 





2.2 





2.9 





40 



3.1 





3.7 





4.9 





50 



4.2 





5.1 





6.8 





60 



5.3 





6.5 





8.6 





70 



6.2 





7.9 





10.2 





80 



7.2 





9.0 





11.7 





90 



8.1 



Decade measure- 



10.1 



Decade measure- 



12.8 



Decade measure- 



100 



8.9 



ments on 886 



11.2 



ments on 271 



13.8 



ments on 130 



110 



9.7 



f 1.5-foot stumps 



12.2 



3-foot stumps 



14.7 



f 2-foot stumps 



120 



10.5 



98-370 years old. 



13.1 



91-483 vears old. 



15. 5 



72-332 vears old. 



130 



11.2 





14.0 





16.2 





140... 



11.7 





14.7 





16.9 





150 



12.2 





15.2 





17.5 





160 



12.7 





15.8 





17.9 





170 



13.1 





16. 3 





18.4 





180 



13.4 





16.7 





18.8 





190 



13, 8 





17. 





19.3 





200 



14.2 





\ 17.5 





I 19.6 





Age. 



Presc 



€ 



)tt National For- 

 st, Arizona. 



Stevens County, Wash. 



Butte and Madera coun- 

 ties, Cal. 



Diam- 





Diam- 





Diam- 







eter 



breast 



Basis. 



eter 



breast 



Basis. 



eter 



breast 



Basis. 





high. 





high. 





high. 





Years. 



Inches. 





Inches. 





Inches. 





10 







f 





1 0.8 





20 



2.2 





2.2 





4.1 





30 



4.3 





4.5 





7.1 





40 



6.3 





6.3 





9.7 





50 



8.1 





7.9 





12.2 





60 



9.5 





9.4 





14.3 





70 



10.8 





10.8 , 





16. 2 





80 



12.0 





12 2 





17.8 





90 



13. 



Decade measure- 



13.5 



Decade measure- 



19.4 



Decade measure- 



100 



111 



{ ments on 189 \ 



14.9 



ments on 210 



20.9 



ments on 422 

 f 2.5-foot s£umDS 



110 



15.2 i 



( 2-foot stumps 



16.2 



f 3-foot stumps 



22.2 



120 



10.2 



31-308 years old. 



17.6 



85-300 vears old. 



23.4 



21-248 years old. 



130 



17.1 





18.9 





24.5 





140 



18.0 





20.1 





25.5 





150 



18.7 





21.2 ! 





26.5 





160 



19.4 1 





22.2 





27.3 





170 



20.0 1 





23. 2 





28.0 





180 



20.5 





24.0 ! 





28.7 





190 



21.0 





24.7 ! 





29.2 





200 



21.6 





V 25. 3 ! 





[ 29.7 





[Cir. 127] 



