160 THE FINANCIAL RESULTS OF FORESTRY. 



Example. — Let S =■ 404 shillings ; e = 3 shillings ; p = 2i 

 per cent. ; c- = 60 shillings ; data on page 120. Then : — 



,0-51 (1,055- 985 - 3) 100 , ^ , 



^'■^= 404 + 985 =4-8percent. 



Go-61,, ^ (1,639_-1,563 -^3) 100 ^ 

 ^' 404+1,563 



;o-:i ^ ^ (2,26 9 - 2 ,187 - 3) 100 ^ ^.q 

 ^'■' 404 + 2,187 



80-81 ., ^ (2, 944 - 2,860 - 3) 100 ^ ^-s 

 ■' 404 + 2,860 



,,„_,ip ^ (3,646 - 3,558 - 3) 100 ^ ^-i 

 404 + 3,558 



It will be observed, that the forest per cent., from the 50th 

 year onwards, is at first large but falls with the advancing age 

 of the wood. At the year 80 — 81 it is equal to the general 

 per cent, p = 2J % ; after that time it is smaller than 2^ %. 

 Hence, the current annual forest per cent, is utilised to 

 ascertain the financial ripeness of a wood, a matter which 

 will be dealt with further on. 



ii. Mean Annual Rate of Interest. 



The mean (or average) rate of interest is ascertained by 

 converting all net returns into an equal annual rental and 

 dividing it by the producing capital. That quotient multiplied 

 by 100 gives the mean annual forest per cent. 



The best time for making the calculation is the commence- 

 ment of the rotation. At that time, the annual net rental is 

 represented by the expression — 



/ r,.+ 7;,xro/-"+ . . . +r,xrOj/-^-cxi-oy _ .a .^ 



V I'Oi;'--! / ^" 



The producing capital at the commencement of the 

 rotation is equal lu the cost value of the soil = be. lience, 



