EXPECTATION VALUE. 127 



again. A second maximum may occur owing to a sudden 

 heavy increase in the value of the growing stock. Under an 

 excessively high rotation, the expectation value of the soil 

 would again become negative. 



Example. — Making the calculation for successive rotations 

 for a Scotch pine wood, with the same conditions as before, 

 the following amounts of the expectation value are obtained : — 



S^ for a rotatic 

 Se „ 



Se „ 

 Se „ 

 S, „ 



Se ., 



Se ,. 



Se „ 



■ s, ,, ,, .. 



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. The higher the rotation beyond 80 years, 

 the less favourable are the results. 



c. The Time when the Intermediate Returns are Reatised. 



The earlier the intermediate returns occur, other matters 

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



Example. — The present value of a thinning, worth 86 

 shillings, made in the year 60, and again every 100 years, is = 



86 X l-02o*« 



1-0251 



= 21 shillings. 



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

 every 100 years, its present value would be = 



86 X 1-025'" ,^ 1 ..y 

 1^25^00^1 =^'^^^^^^^^S- 



