LIFE HISTORY OF A TREE. 



127 



it remained until it was cut eighteen years later. When cut it 

 measured fifty-five feet high, thirteen inches through at the base 

 and contained 29.95 cubic feet of timber. During the last ten 

 years it had made an average annual increase of 1.5 cubic feet. 



This study brought out the following facts: (i) While 

 rapid upward growth is being made the lateral accretions are 

 slight. (2) Large accretions accompany full leafage. (3) 



Figure 33. White Pine crowded and then open grown. 



After the surrounding growth is killed, the tree begins to 

 strengthen the portion which receives the greatest strain by wind, 

 that is, the lower part of the trunk. (4) In approaching the 

 top of the tree the accretions are found to diminish as each live 

 branch is passed. 



Figure 34 shows a section of a White Pine that was entirely 

 open grown. This tree was cut when fifty-six years old, and 

 measured eighteen inches in diameter on the stump, eight- inches 

 at twenty-five feet above the stump and forty-eight feet in height. 

 The volume of the stem when cut was 28.85 cubic feet; the 



