GROWTH OF TREES AND FORESTS 



191 



for hemlock under similar conditions to reach the height of two 

 feet, then the total age of the tree will be estimated to be one 

 hundred and seventy-five years. 





By permission of S.J. Record. 



Fig. 64. Cross section of a hardwood (black ash) highly magnified showing the annual 

 rings of growth. A to B is one season's growth. 



2. Diameter Growth. 



For scientific purposes diameter growth should always be 

 studied at a cross section taken at breast height, but as a matter 

 of fact it is usually studied on the stumps of trees cut for lumber- 

 ing. As the growth near the swelling of the roots is slightly 

 greater than that higher up, the results are not entirely accurate. 



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