YIELD AND FINANCIAL RESULTS. 213 



means that all money is taken out of an investment which 

 gives 3 per cent. : — 



3,900 + 10 X (1-03)^0 + 76 X (1-03)^" 

 + 220 X (l-03)-''^ + 270 X (l-03)-'J + 



Value of soil = BOO X (l^" - 90 X (IW^ _± 



(1-03)'" - 1 -03 



If this calculation is carried out, ^Ye obtain 



Value of soil = 576.s. = £28 16s. 



If the calculations with the other per cents, are carried out, 

 we obtain the following : — 



£ .V. fl. 



Value of soil calculated with 2^ per cent. = 45 10 

 „ 3 „ = 28 16 



„ 3^ „ = 18 4 



„ 4:" „ = 11 1 



„ 41 „ =630 



„ 5 „ = 2 15 



These values are now plotted with the per cents, as abscissa 

 and the soil values as ordinates and a curve drawn through 

 them, when the diagram on the next page is obtained. 



From this diagram the per cents, yielded under different 

 soil values were read off and entered in the above table for 

 larch. The per cents, for other species were ascertained in 

 the same way. 



Enough has been said to show how important the finan- 

 cial aspect of forestry is. This has been recognised in 

 many parts of the world, but not yet sufficiently in Britain. 

 In this country the imj^ortance of natural history, and 

 more particularly botany, has up to date held the field, 

 while the financial or mathematical aspect of the forest 

 industry has been overlooked. No doubt, a forester must 

 be a good sylviculturist, and to be that, he requires to 

 have a fair knowledge of botany, geology, and entomology, 

 but that alone will not make him a competent forester. 



