RATE OF INCREASE. 



61 



rapid upward growth is being made the lateral accretions are 

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

 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 approach- 

 ing the top of the tree the accretions are found to diminish as 

 each live branch is passed. 



Figure 10 shows a section of a White Pine that was en- 

 tirely open grown. This tree was cut when 56 years old and 



Figure 9. White Pine crowded and then open grown. 



measured 18 inches in diameter on the stump, 8 inches at 25 

 feet above the stump and 48 feet in height. The volume of 

 the stem when cut was 28.85 cubic feet; the accretion during 

 the last ten years was 12.52 feet which is equivalent to mean 

 annual increment of 1.25 feet. 



As the live branches of this tree occupied the whole trunk, 

 the timber was very knotty. A proper crowding would have 

 kept it from forming large branches on the lower trunk, stim- 

 ulated its upward growth and prevented so large an incre- 



