314 DETERMINATION OF THE YIELD. 



volume calculated, and the increment for half the number of 



years in the period, ^, added. The total of the volume thus 

 2 



obtained is divided by the number of years in the period, so as 

 to obtain the average annual yield during the first period. 



For an example see Appendix A, at page 349, where the 

 working plan for the communal forest of Kruuibach, a village 

 in Hesse-Darmstadt, has been given. This working plan is 

 being actually followed. 



b. Merits of the Method. 



The method is simple, and can be applied by any intelligent 

 manager. It establishes the normal state within one rotation, 

 if no disturbing events occur. At the same time it may yield 

 very uneven returns during the first rotation, though this can 

 be avoided to some extent by suitable shiftings. Although the 

 method is much less rigid than that of fixed annual coupes, it 

 is often difficult to produce during the first rotation a proper 

 grouping of the age classes; more especially, too large cutting- 

 series are likely to be established. 



Another disadvantage is that a surplus of growing stock may 

 be dragged over a whole rotation, whereas it should be removed 

 as quickly as possible ; or, on the other hand, it may take a 

 whole rotation to make good any deficit of growing stock. 



For a financial management the method is little adapted, 

 except in so far that it introduces order into the management. 

 It gives only a limited latitude to the forester to hold over 

 vigorous woods, or to cut over those which are deficient in 

 increment. 



2. The Method of Periods by Volume. 



a. Description of the Method. 



The woods of a forest are so allotted to the several periods 

 of a rotation that each yields the same, or approximately the 

 same, volume. In some cases only the final returns are thus 



