COPPICE WITH STANDARDS. 237 



c. Coppice and Coppice with Standards. 



The calculation for simple coppice is the same as in the 

 case of clear cutting in high forest. 



For coppice with standards forest the calculation must be 

 made separately for under- and overwood, and the results 

 added together. The former is of small account, as the 

 presence of the overwood reduces the quantity of the under- 

 wood considerably. 



The calculation of the normal growing stock of overwood 

 is a complicated and uncertain operation, and at the best 

 only of theoretical value. It must be based upon the number 

 of trees in each age class, and the average volume per tree 

 in each, somewhat in the following manner : 



If the normal number of trees in each of the r, 2 r, 

 3 r . . . old age gradation is known, and also the volume of 

 the average tree in each of these gradations, then it can be 

 assumed that the trees increase, within each class, in volume 

 according to an arithmetical series ; this makes it possible to 

 interpolate the volume of the trees r +1, 2 r + 1 . . . years 

 old. In that case the normal growing stock of the first age 

 class would be expressed by 



where F r + 1 represents the volume of all trees r + 1 years old, 

 and F 2r that of all trees 2 r years old. In the same way 

 the next age class would be represented by 



and so on. Adding all positions together the normal growing 

 stock of overwood comes to : 



This amount does not comprise the youngest age class of 

 all, which still forms part of the underwood. 



