i8 



FORESTS AND MANKIND 



wood cells the tree grows in diameter and height. So as the 

 years pass periods of growth and rest follow each other and the 

 limits of each year's growth become marked in the wood of 

 the trunk, where they appear as ever enlarging rings. By count- 

 ing their number one can very closely tell the age of a tree. 

 These rings also tell something of the changing conditions 

 under which the tree lived. Some rings show years when the 



TREE CLASSES 



Foresters divide the trees of the forest into three main classes. The mature trees 

 that are the tallest of the forest, he calls Dominant (D) trees. Those not quite tall 

 enough to reach this class yet able to crowd into the sunlight are the co-dominant 

 (CD). The trees that have fallen behind in the race and are cut of! from the 

 sunlight, the forester calls Suppressed (S). 



It is from the Dominant class that the bulk of the world's timber comes. 



tree grew rapidly and some in which it put on hardly any 

 growth at all years when drouth may have prevented growth, 

 or when some overshading tree stunted it. It has even been 

 claimed that by the rings of the age-old sequoias, the oldest 

 living things in the new world, we can read records of the dry 

 years chronicled in the Bible. 



