NORWAY PINE IN THE LAKE STATES. 
17 
Table 5. — Minimum, average, and maximum heights based on age, Bayfield County, 
Wis. 
Height. 
Height. 
Age 
(years). 
A ^ 
(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 
