12 



BULLETIN 820, U. S. DEPARTMENT OF AGRICULTURE. 



Table 6. — Measurements^ on 22 trees in a fairly dense, somewhat mature to overmature 

 stand of jack pine in the Upper Peninsula of Michigan. 



[The trees were cut for saw logs. Stand located on a low sandy ridge, slightly elevated above a muskeg 

 swamp on one side, and above a lower area of spruce, tamarack, and some jack pine on the other. 

 Soil, coarse sand underlaid with clay subsoil. See PI. VIII.] 



Average. 



Maximum. 



Minimum. 



Age years . . 



Height feet . . 



Diameter, breast high inches. . 



Volume in board feet, Scribner decimal rule 



Vohune in board feet (mill scale of possible round-edge) 



Clear length feet . . 



Merchantable length do 



Number of 16-foot logs 



104 



72.5 



12.2 

 128 

 175 



34 



46.4 

 3 



125 

 88 

 17 



290 



430 

 50 

 60 

 3| 



Measurements by Huber C. Hilton, 1918. 



Table 7. 



-Rate of growth, in diameter and height, of jack pine, on good sites in western 

 Ontario.^ 



Age 



Diameter 

 breast 

 high. 



Height. 



Age. 



Diameter 

 breast 

 high. 



Height. 



Years. 

 5 



Inches. 



'6.' 8 

 2.0 

 4.0 



■ 5.8 

 7.1 

 8.1 

 8.9 

 9.6 



10.3 



11.0 



Feet. 



1.5 



8 

 17 

 28 

 36 

 • 42 

 46 

 50 

 54 

 58 

 61 



Years. 

 60 



Inches. 

 11.7 

 12.4 

 13.0 

 13.5 

 14.0 

 14.5 

 14.9 

 15.2 

 15.6 

 15.9 

 16.2 



Feet. 

 64 



10 



65 



67 



15 . . 



70 



70 



20 



75 



72 



25 .... 



80 



74 



30 . . . . ■ 



85 



76 



35 



90 



77 



40 



95 



79 



45 



100 



80 



50 



105 



81 





110 



81.5 









1 From an article by L. M. Ellis, in the Forestry Quarterly, for Mar. 1, 1911. 

 Based on 100 trees. 



Table 8. — Average rate of grov^th, in diameter, of 50 representative jack pine trees, on 

 the Riding Mountain Reserve, Manitoba, Canada.'^ 



Age. 



Diameter 



breasthigh 



(outside 



bark). 



Age. 



Diameter 



breasthigh 



(outside 



bark). 



Years. 

 10 



Inches. 

 0.5 

 2.8 

 5.4 

 7.3 

 8.8 



Years. 

 60 



Inches. 

 10.1 



20 



70 



11.0 



30 



80 A 



90 



11.7 



40 



12.2 



50 



100 



12.6 









1 From Bulletin 6, "Wood-Using Industries of the Prairie Provinces," of Canadian Forestry Branch. 

 This bulletin states that: "Jack pine in closed stands on the Riding Mountain Reserve reaches 60 to 80 

 feet in height by 12 to 18 inches in diameter, with straight, clear trunks yielding a good grade of saw and 

 tie timber. But where open grown they are a mass of limbs right to the ground, and of little value, 

 even for firewood. 



Table 3, relating to trees grown in Cass County, Minn., shows a 

 less rapid diameter growth than Table 2, which refers to other trees 

 grown in the same county, probably because those covered in Table 

 3 are comparatively open grown, thrifty second growth. 



