14 THE SCHOOL BOOK OF FORESTRY 



One can tell the age of a tree by counting the 

 number of annual rings. Sometimes, because of 

 the interruption of normal growth, two false 

 rings may be produced instead of a single true 

 ring. However, such blemishes are easy for the 

 trained eye to recognize. Heartwood does not oc- 

 cur in all varieties of trees. In some cases, where 

 both heartwood and sapwood appear, it is difficult 

 to distinguish between them as their colors 

 are so nearly alike. Because it takes up so much 

 moisture and plant food, sapwood rots much more 

 quickly than heartwood. The sapwood really 

 acts as a pipe line to carry water from 

 the roots to the top of the tree. In some of our 

 largest trees the moisture is raised as high as 

 300 feet or more through the sapwood. 



Strange though it may seem, trees fight with 

 each other for a place in the sunlight. Sprightly 

 trees that shoot skyward at a swift pace are the 

 ones that develop into the monarchs of the for- 

 est. They excel their mates in growth because 

 at all times they are exposed to plenty of light. 

 The less fortunate trees, that are more stocky 

 and sturdy, and less speedy in their climb toward 

 the sky, are killed out in large numbers each year. 

 The weaker, spindly trees of the forest, which are 



