12 
years. Many ash trees have twenty-five rings to the last 
inch. This is very characteristic of ash and is due to its 
capacity to endure congestion or crowding of the crown. Oak, 
on the other hand, demands space. For these characteristics 
we require new terms. We might say that oak is space de- 
manding, while ash is crowd enduring. 
Since, however, increase of diameter is closely. associated 
with clear length of bole and crown development, these two 
latter factors must be studied before it can be ascertained 
how far this rapid increase of diameter of oak can be main- 
tained and how far the slow growth of ash may be avoided. 
The curves for diameter growth are in no way final in them- 
selves since they are in no way correlated with clear bole or 
radius of crown. All that they do show is the characteristic 
type of diameter growth of each. Oak shows a desirable 
diameter growth while ash shows in its latter years very 
undesirable growth. 
B. INTERRELATION OF DIAMETER, BOLE, AND 
CROWN 
An examination was next made of the dominant trees in the 
age class sixty to seventy years, and for each tree the height, 
length of clear bole, diameter breast high and radius of 
crown were taken. In measuring the crown four radii were 
taken and the mean calculated. The measurements were re- 
peated later on a number of the same trees, other radii being 
used, and it was found that the differences resulting were 
small and could be neglected. Trees having very irregular 
crowns were rejected. 
The term clear bole was taken to mean the length to any 
branch, dead or alive, beyond which there was not a clear log 
length. This gives correct results so far as the uncultivated 
forest is concerned, but it does not correctly indicate the 
length of clear bole obtainable under systematic control. 
However, it has been retained as introducing a conservative 
element into the conclusions. This will be referred to again. 
