METHOD OF PERIODS BY AREA. 313 



of the periodic coupe becomes = '—^. Unless this is 



done, the periodic yields in the second and follo^Ying■ rotations 

 will not be equal. 



In allotting the woods to the several periods, that to be 

 dealt with first receives the oldest woods and those with the 

 most deficient increment, taking into consideration a suitable 

 arrangement of the cutting series ; the allotment to the other 

 periods is made according to the age of the woods, with due 

 consideration to a suitable grouping of the age classes. If 

 then the totals in the several periods differ, shiftings are made 

 by moving certain areas backward or forward, until each period 

 contains the same, or approximatel}^ the same, area. 



The woods placed into the first period are measured, their 

 volume calculated, and the increment for half the number of 



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



obtained is divided by the number of years in the period //, 

 so as to obtain the average of the final annual yield during 

 the first period. To this amount the thinnings must be 

 added. 



For an example see Appendix lY., A, at page 882, where the 

 working plan for the communal forest of Krumbach, a village 

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

 being actually followed. 



1). Jlerils 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. 



Another disadvantage is, that a surplus of growing stock 



