THE THEORY AND PRACTICE OF WORKING PLANS 



15 



in area or amount, or (in selection forest) in number of trees 

 (Altersklassenverhaltniss) . 



Similarly, distribution of diameter classes in its strict sense 

 means the location and area of each stand of a given diameter 

 class in the forest. In a general sense it means the per cent 

 of area occupied by each diameter class in the forest. 



Diagram C 



•I \ li_s 10 20 30 -10 



70 SO 'JO 100 



A table or diagram showing the proportion or amount of 

 each age class in the forest is called an age class record. This 

 may be expressed in percentages or in actual area. Similarly, 

 there may be a diameter class record. 



The correct distribution of the age classes is theoretically 

 like a series of equal sized steps, growing higher along the 



