238 



THE NORMAL GROWING STOCK. 



Example : 



Area of a coppice with standards forests = 100 acres. 

 Rotation of underwood = 20 years. 

 ,, overwood = 100 ,, 



100 

 Number of overwood classes = t - = 5. 



Area of each coupe = 5 acres. 



G n = 10x9634-5 -96,345 cubic feet, or per acre = 963 cubic 

 feet. 



d. The Selection Forest. 



The growing stock of a normal selection forest ma}' be 

 placed equal to that of a forest under the clear cutting system, 

 as all the age gradations are represented in a similar way, 

 though differently arranged over the area ; hence it can be 

 ascertained by summing up the quantities given in a yield table. 

 At the same time the calculation is likely to be less accurate, 

 since the younger age gradations stand under the shade of the 

 older trees, and it is difficult to say in how far the loss of 

 increment of the former is covered by an increased increment 

 of the latter. 



