VON MANTEL'S METHOD. 323 



On the other hand, Hundeshagen's method has this great 

 advantage, that the increment need not be determined, such a 

 determination being at all times beset by difficulties and uncer- 

 tainty. All that the method requires is a suitable yield table, 

 and the measurement of the growing stock actually standing 

 in the forest. Hence, the method is by no means to be 

 despised, if a general plan is added indicating the grouping of 

 the age classes to be aimed at. For the rest, it leaves a free 

 hand to the manager to shape the management in accordance 

 with the requirements of each case, as long as the volume 

 determined by the formula need not be rigorously cut. It may 

 reasonably be assumed that Hundeshagen himself expected 

 this. 



3. Von Mantel's Method. 



Von Mantel, in arranging for the determination of the yield 

 of certain forests in Bavaria, laid it down that this should be 

 done according to the formula 



A 1Y* Id ^ ea ^ G' rowm stock of the forest _ real G 

 Half the number of years in the rotation r 



2 



This formula rests upon the same basis as Hundeshagen's 

 method, if for the latter the normal growing stock is cal- 

 culated with the final mean annual increment. Hundeshagen's 

 formula 



V 

 V f7* 



* ^ * ~~ 



G: 



goes in that case over into 



j r r 



n o o 



The cutting of the yield according to Yon Mantel's formula 

 will gradually lead to the establishment of the normal growing 

 stock, as the following considerations will show : 



Supposing the real growing stock (under which Yon Mantel 



Y 2 



