YIELD AND FINANCIAL RESULTS. 49 



Supposing now that the cultivation of larch is undesirable 

 on account of the larch disease, and that Scotch pine and 

 spruce are planted for pit timber. Assuming further that we 

 get altogether 3,000 cubic feet of timber at the end of forty 

 years, valued at 6d. a cubic foot, and that the thinnings are 

 left out of account, we obtain the following results : 



Per cent. 



Cost price of land = .1, interest . . = 5*7 



,5 55 A 55 . 5*d 



= 4- 4.-Q 



5 > 5 J? ' *X V 



- 6 4-5 



= 8 = 4-2 



= 10 3-9 



= 15 3-4 



,, = 20 3-0 



= 25 . . = 2-7 



= 30 2-5 



Even in that case the operation pays well, as such land is 

 not likely to cost more than ,10 an acre, and probably not 

 more than 4 to <6. 



I could give many other examples, but those already given 

 will show that, on financial ground, the afforestation of 

 mountain and heath land rests on a safe basis. 



As I received several enquiries regarding the manner of 

 making calculations like those given above, I shall here add, as 

 an example, the details for larch under a rotation of 70 years. 



All calculations must be made with compound interest. 

 Taking the returns for larch given above, as well as the cost 

 of planting '4 10s., and annual expenses 4s., a number of 

 trial calculations are made with, say, 2J, 3, 3J, 4, 4J, and 5 

 per cent., so as to ascertain the value of the land for larch 

 planting. The formula for doing these calculations will be 

 found in Volume III. of my " Manual of Forestry," p. 126, 

 seventh line from bottom. One example will show how this 

 formula works, say by calculating with 3 per cent., which 



