HEYER S METHOD. 329 



the woods are thereby altered. This process is con- 

 tinued until the requirements of the method are 

 realised, that is to say, until each period contains the 

 same area, and, at the same time, the volume neces- 

 sary to meet the yield as calculated under (d). As 

 already indicated, the forester must, in this respect, be 

 satisfied with approximate results. 

 (/.) The regulation of the yield is restricted to final returns. 

 The intermediate returns are estimated only for the 

 first period, or part of it, by means of yield tables, or 

 past experience, and added to the final yield. 



3. Merits of the Method. 



The method is one of great precision. On the other hand, 

 it is very complicated, and it calculates the increment, as well 

 as the normal and real growing stock, incorrectly, as in the case 

 of the Austrian method. The latter objection could be removed 

 by using suitable yield tables, instead of the final mean 

 annual increment, for the calculation of the increment and 

 normal growing stock, and by measuring the growing stock 

 actually standing in the forest. Nevertheless, the method 

 involves great labour, and the necessary calculations are of 

 an uncertain nature. 



