XOKWAY PUSTE IX THE LAKE STATES. 



17 



Table 5. — Minimum, average, and maximum heights based on age, Bayfield County, 



Wis. 







Height. 









Height. 





Age 

 (years). 









Age 

 (years). 























Minimum. 



Average. 



Maximum. 





Minimum. 



Average. 



Maximum. 





Feet. 



Feet. 



Feet. 





Feet. 



Feet. 



Feet. 



10 



7 



12 



19 



110 



74 



92 



102 



20 



16 



35 



56 



120 



78 



94 



104 



30 



26 



58 



78 



130 



81 



95 



105 



40 



34 



70 



86 



140 



83 



96 



107 



50 



43 



77 



91 



150 



86 



98 



108 



60 



50 



82 



94 



160 



88 



99 



109 



70 



56 



85 



96 



170 



89 



100 



110 



80 



62 



88 



98 



180 



91 



101 





90 



67 



90 



99 



190 



93 



103 





100 



71 



91 



101 



200 



94 



104 





Table 5 apparently indicates that the height growth of maximum 

 trees is very rapid for 40 years and soon afterwards dwindles to almost 

 nothing. In reality the height growth is much more gradual and 

 continues longer than indicated in the column headed " Maximum." 

 The most rapidly growing trees, which apparently show a height of 

 86 feet for 40 years, are merely trees which when 86 feet high have 

 a diameter of 13.8 inches, this being the average height of a tree of 

 that diameter. As a matter of fact, a tree which grew 13.8 inches 

 in diameter in 40 years could not reach a height of 86 feet in the 

 same time. The column containing the average figures gives a 

 more nearly correct idea of the growth in height. 



Table 4 shows the relation between diameter and height, 



DIAMETER GROWTH. 



The diameter growth of a tree is influenced to a very marked 

 extent by the quality of the soil and the density of the stand. This 

 effect is clearly shown in the following classes : ( 1) Dominant trees. 

 According to their past history in the stand these may be divided 

 into those which have survived to reach merchantable size, those 

 which occupy a dominant position in the stand, and those which 

 have been suppressed for about 100 years by jack pine; (2) inter- 

 mediate trees; and (3) suppressed trees. The growth in diameter 

 of these different classes of trees, with different crown development, 

 is shown in Tables 6 to 10. Table 6 gives the best, average, and 

 slowest growth in diameter on good soil in Bayfield County, Wis., 

 for trees which survived to reach merchantable size. 

 55040°— Bull. 139—14 3 



