11 
TREE FORM IN THE FINAL STAND 
A. Diameter GRrowTH 
In studying the growth and development of oak and ash 
stump analyses of oak and ash were first made. These stumps 
were of trees which had produced the highest grade lumber in 
the district. They were of an age mainly between sixty and 
seventy years, with a few running up to seventy-five years. 
All the subsequent data were collected on sites similar to 
those on which the stumps occurred. The ages of the stands 
were similar to those of the stumps. No data were obtained 
for ages above seventy-five years. This was because the 
stands become merchantable at about seventy years and are 
felled at or about that age. So far, then, as local practice 
goes, seventy years may be regarded as the usual rotation. 
Stump taper curves were made from neighboring trees and 
from these curves the diameter at breast high of the various 
stumps determined. The amount of growth in diameter for 
each diameter class was also ascertained. 
Figure 1 gives the results of the examination of forty-two 
oak stumps and twenty-three ash stumps. The curves are for 
wood only and show some very characteristic features. In 
the early years, the growth of ash is much faster than that of 
oak. These forests have arisen mainly as sprouts from small 
advance growth, and hence the growth is much greater than 
would be the case if the tree originated from seed. Ash grows 
better under shade than does oak, and hence forms a better 
root system for the subsequent sprouts. The size of the 
sprouts is directly governed by the root system of the ad- 
vance growth and the size of the latter is largely a question 
of age. 
The main feature of the graphs is, however, the course of 
the curves at the seventieth year. Oak is still growing vigor- 
ously and is producing wood at the rate of .2” a year, or for 
ten years two inches of diameter. Ash, on the other hand, is 
only producing wood at the rate of one inch for every ten. 
