22 
THE) STORY OR THE) OAK TRE)R 
Each year, commencing in the Spring, onto the outer 
surface of the cambium layer—that is, the part next to 
the bark—grows a new strip of bark. This new strip, 
together with other growth within the trunk, pushes out 
and strains the old bark until it cracks and dies. Then it 
falls off the tree and the new bark takes its place. Trees, 
just like boys and girls, do their most rapid growing be¬ 
tween March and July. Did you know that? Boys and 
girls grow tall in Spring, and in the Fall they put on 
weight,—like the plant they store up food for future 
use, because fat is stored food. In early summer, at the 
time of the tree’s most rapid growth, you can pull a strip 
of bark from an oak without hurting the tree. Pull off 
the bark, and underneath you will see the cambium. 
Then, if the cambium be carefully shaded from the 
scorching sun, or if the weather remain moist and cloudy 
for a few days, the cambium will grow a coat of bark 
right over the bared and tender surface—provided the 
surface has not been bruised or broken. A young tree 
can be stripped of its bark for several feet and heal its 
own wound, but to strip a tree is not a kind thing to do. 
At the same time that the cambium is growing its yearly 
outside strip, it is also adding an inside layer. These 
yearly layers can be plainly seen on the sawed-off trunk 
of an oak. They go round and round, and if you count 
them you will know just how old the tree is, because each 
