Periodical Literature 265 



As regards the figuring of the normal stock, the author quotes 

 Heycr's conception, commending it: "For purposes of budget 

 determination it is more nearly correct to base the normal stock 

 not on the normal but on the actual felling age increment, whereby 

 the difference between Sa and S„ is reduced to an unequal sum 

 of age units." And he adds: "It is not the function of budget 

 regulation to increase the increment of open and poorly stocked 

 stands but that of silviculture. By assimiing a certain yield 

 capacity and reducing the budget to correspond, poorly stocked 

 stands do not become closer; but the danger is invited of delaying 

 the removal of the poor stands or of acctimulating over mature 

 stands: the introduction of the yield capacity (normal increment) 

 in budget determination should be abandoned." 



Having determined the felling budget in general on the basis 

 of the rotation, it should hold in general for the next two or three 

 decades, and the author prefers three because variations in condi- 

 tions of stands, market and needs of owner are more easily balanced 

 in the longer time. Silvicultural considerations may make it 

 desirable to distribute the budget unevenly over the decades. 

 Altogether, the mathematical sanction of the budget and formula 

 determination, as Heyer pointed out, is to serve only as a general 

 guide. 



The above example is then extended under the assimiption that 

 the manager has chosen r = 80, and wants to change to 100. 



100 



The annual felling area becomes — = 1.25 acres; the Sn figures 



80 



up 350,000 cubic feet; the S„ for 100-year rotation figures by 

 formula —I„ to 420,000; the /« based on the average felling 



ages as in the above table sums up to 8,000 cubic feet. Placing 

 these values in Heyer's formula 



t = 8000+ ?^5.590zf?a229 = 8000 - ™229. 



e e 



To determine e, we have the equation 

 _ rnla 80x70000 



^~ It 9 ~ 40X8000-350000 "~^^^ 

 2 " " 

 This shows that the 80-year rotation is not adapted to securing 

 the S„; we would overcut the la and increase the stock difference. 



