EXPECTATION VALUE. 129 



S e for a rotation of 30 years . = 105 shillings. 



S e ,, ,, jj 40 . = + 50 



S e 50 . = + 121 



S e j, 60 . = + 196 



S g 70 . = + 236 



S e 80 . = + 250 fn^n 



S e 90 . = + 245 



S e 100 . = + 229 



S e j, 110 . = + 207 



S e 120 . = + 180 



The above data show that, financially, the most favourable 

 rotation must be that under which the expectation value 

 reaches its maximum ; in the above example a rotation of 

 about 80 years. 



c. The Time when the Intermediate Returns are Realized. 



The earlier the intermediate returns occur, other matters 

 being the same, the higher will be the expectation value. 



Example. The presentvalue of a thinningj.worth 86 shil- 

 lings, made in the year 60, and again every lOO^years, is = 



86xl'025 40 01 ... 



5MZT = 21 Billings. 



If the same thinning were made in the year 30, and again 

 every 100 years, its present value would be = 



It follows that strong thinnings made at an early age can 

 considerably increase the expectation value. At the same time 

 it must not be overlooked that the small material obtained from 

 early thinnings is not always saleable at remunerative rates ; 

 moreover, such thinnings may disastrously affect the later 

 returns, especially the final yield, so that the advantage gained 

 in the first instance may be more than counterbalanced by loss 

 later on. 



VOL. III. K 



