16 



BULLETIN 139, U. S. DEPARTMENT OF AGRICULTURE. 



top and partially or completely suppress the other pines. The height 

 growth of Norway pine is best in full sunlight, when slightly crowded. 

 The average height growth of saplings in fairly well-stocked stands 

 is shown in Table 3. No measurements were made of the growth in 

 height of older trees. From the measurements of height on diameter, 

 Table 4, and the measurements of diameter on age, Table 7, it was 

 possible to construct a table of height growth based on age. This 

 table is based on the assumption that diameter and height growth 

 are roughly proportional. Thus, if the height of a tree of a given 

 diameter is known and also the age of the diameter corresponding to 

 the height of this tree, the age of the tree having this height is 

 thereby determined. Table 5 has been constructed after this plan. 

 It shows the average height of trees of different ages. Figures for 

 minimum and maximum heights are also given. The maximum 

 trees grew in Wisconsin in mixture with white pine and were domi- 

 nant. The minimum figures are for slow-growing suppressed trees. 



Table 3. — Height growth of saplings in northern Minnesota. 



Age 

 (years). 



Height, 



Age 

 (years). 



Height. 



Age 

 (years). 



Height. 



I Age 

 ;(years). 



Height. 





Feet. 





Feet. 





Feet. 





Feet. 



1 



0.3 



8 



4.9 



15 



15.0 



22 



23.0 



2 



.6 



9 



6.0 



16 



16.7 



23 



23.8 



3 



1.0 



10 



7.2 



17 



18.1 



24 



24.6 



4 



1.5 



11 



8.5 



18 



19.3 



25 



25.5 



5 



2.2 



12 



9.9 



19 



20.4 



26 



26.3 



6 



2.9 



13 



11.4 



20 



21.3 



27 



27.1 



7 



3.0 



14 



13.1 



21 



22.1 



28 



28.0 



Table 4.- 



■Minimum, average, and maximum heights based on diameter, Minnesota and 

 Wisconsin. 



Diameter 





Height. 





Diameter 





Height. 





breast- 

 high 









breast- 

 high 





















(inches). 



Minimum. 



Average. 



Maximum. 



(inches). 



Minimum. 



Average. 



Maximum. 





Feet. 



Feet. 



Feet. 





Feet. 



Feet. 



Feet. 



1 



11 



12 



16 



18 



61 



88 



112 



2 



16 



20 



28 



19 



63 



90 



113 



3 



18 



27 



41 



20 



66 



91 



114 



4 



21 



34 



52 



21 



68 



92 



115 



5 



24 



41 



63 



22 



71 



94 



116 



6 



26 



47 



72 



23 



73 



95 



116 



7 



29 



53 



80 



24 



76 



96 



117 



8 



32 



58 



87 



25 



78 



97 



118 



9 



35 



63 



93 



26 



SO 



99 



119 



10 



38 



67 



97 



27 



83 



100 



120 



11 



41 



71 



101 



28 



85 



101 



121 



12 



44 



74 



103 



29 



87 



103 



122 



13 



47 



77 



105 



30 



89 



104 



123 



14 



50 



80 



107 



31 



91 



105 



124 



15 



53 



82 



108 



32 



93 



106 



125 



16 



55 



85 



109 



33 



95 



108 



126 



17 



57 



87 



110 



34 



98 



109 



127 



