METHOD OF PERIODS BY VOLUME. 315 



regulated ; in others the intermediate returns are utilized to 

 equalize the yields of the several periods. 



The allotment is based upon the table of age classes ; then 

 shiftings are made, so as to bring woods which have a poor 

 increment early under the axe, and establish, as far as prac- 

 ticable, a suitable grouping of age classes ; then further shift- 

 ings are made, so as to equalize the periodic returns. The 

 result represents the general working plan for the first rota- 

 tion. It will be observed that, in the majority of cases, the 

 areas placed into the several periods will be uneven, resulting 

 in uneven returns during the second rotation, unless a fresh 

 allotment is made. 



Example : In Appendix B, page 362, only the final re- 

 turns have, for simplicity's sake, been equalized. The data 

 are those of the Krumbach communal forest given in 

 Appendix A. 



As the future returns have to be estimated for a whole rota- 

 tion, it is evident that yield tables must be used ; accordingly 

 the above general working plan has been based upon the data 

 for beech high forest, given at p. 123. After making the 

 shiftings indicated in the general working plan, the volumes 

 allotted to the several periods stand as follows : 



Periodic Yield. Annual Yield. 



I. period -189,393 cubic feet. 9,470 cubic feet. 



II. -195,474 9,774 



III. -173,919 8,696 



IV. -188,240 9,412 

 V. -194,845 9,742 



Total- 941,871 9,419 



An attempt to equalize the returns further would necessitate 

 the cutting up of compartments, which is not desirable. 

 The areas placed into the several periods are : 



