33 
Both of these agree with the diameter and height of Table 
XVIII for thirty years. Hence, we may assume that the cal- 
culated crown radius of 3.9 is the correct one for thirty years. 
Measurements in a stand of from fifty to fifty-five years 
gave a crown radius 6.8. This latter would be correct for 
fifty-two years. The average height of seventy-three is fairly 
comparable with that given in Table XVIII. 
In the case of oak if we join the point 11.2 feet at seventy 
years to the origin we get a crown radius of 1.6 feet at ten 
years. There is not very much difference between this and 
the computed 1.4 feet. However, oak stands need to be kept 
dense in order to prevent as much as possible the large de- 
velopment of side branches. The graph connecting the points 
11.2 feet at seventy years and 1.4 at ten years will put the r 
axis below the origin. 
A stand forty-three years of age with good boles and well 
formed crowns showed an average diameter of 7.1 inches and 
an average height of fifty-nine. The crown radius was 6.7 
feet. While diameter and crown development agree gen- 
erally with the computed measurements for oak on the better 
sites, the height is considerably lower and, therefore, the site 
may be considered to be inferior to those from which the 
measurements in Table VIII were obtained. 
A stand whose age was from fifty to fifty-five years showed 
almost perfect agreement with the measurements in Table 
XVIII. Trees in this stand averaging 9.2 inches for the nine- 
inch diameter class had an average bole of forty feet, a height 
of seventy-six feet and a crown radius of 8.0 feet. In this 
same stand the ten-inch diameter class, averaging 10.1 inches, 
gave an average height of seventy-six feet, a bole of forty-two 
feet and a crown radius of 8.9 feet. 
While the stands available for the ages twenty to sixty 
years were not by any means abundant the results obtained 
from such stands are in agreement with the results derived 
from the assumption that the crown expansion is a linear 
function of time. 
