188 JOURNAL OF FORESTRY 



If, as is more likely to be the case, the first cost is different, but future 



Y C 



ones the same as C, S/ will be — 7^-— (C^ + E), and the 



I .Op" — I 



capital loss C^ — C. 



If annual expenses for protection and other purposes are changed 



Y C ( I Op") 



permanently, S,' will become q n^j ~ ^' ^"^ ^^^ capital 



loss will be E^ — E. If the change lasts for one rotation only, S/ will 

 Y-C(r.Op-) _ E^(,.Op"-.)+E ^^^^ „„! 



I .Op" — I I .Op» ^ 



^^ E'(..Op"-i) + E _ (E--E)(..Op°-i) jj.^^ 



I .Op" I .Op" 



new costs apply to part of one rotation only (b years), S/ will be 

 Y — C(i.Op") r E^Ci.Op'^— I) E(i.Op"-'^ — I) En 



I .Op" — I ' L I -Op^ I .Op" I .Op" J 



_ Y — C(i.Op") _ EMi-Qp^— I) (I .Op") +E(i.Op") 

 — I. Op"— I i.Opb + " 



the loss in capital value will be 



E^ (I .Opb— I) (I .Op") + E (I .Op") _ ^ (E^ — E) (i.Opb— I) 

 I .Opb + " ^ I .Opb 



If the productivity of the soil is reduced, Y will be reduced, so that 

 (simplest case, assuming C and E unchanged) S/ will be 

 Y^-C(i.Op") 

 I. Op"— I 



Y Y^ 



The capital loss will then be — — . If Y^ is different for one rota- 



^ I .Op" — I 



tion only, S/ will be 



Y 



^''^ i.Op°— I Ci.Op" ^ ... Y — Y^ 



— E, and the loss 



I. Op" I. Op"— I • ^ I .Op" 



If invasion by a different species compels the adoption of a different 



Yi — C (i .Op'i) 



rotation (q). S ^ will become ^c ^—^ — E. and the capital 



^^^ ' I .Op^ — I ' ^ 



loss will be ^-^C-OP") - y-C(i.Op^). Where a regenera- 

 I .Op" — I I .Op^ — I 



tion period (k years) is necessary to start the new stand the effect 



will be to increase the length of the first rotation, and S^* will be 



Y_C(i.Op") 



I. Op" — I 



I .Opk 



