On Quality II Soil. The volume of the thinnings to be obtained on 

 Quality II soils may be expected to bear the same proportionate relation 

 to the volume of thinnings on Quality I as their respective total stands, 

 i. e., as 32,000 is to 44,000, or 8 to 11. The thinnings on Quality II soil, 

 however, will be of smaller sizes, hence less valuable. It seems safe 

 therefore, to assume that the total value will not be more than one-half 

 as great. Hence these thinnings will be expected to make only one-half 

 as much from the total costs as on Quality I soil. 



The amount to be deducted from the total costs per acre on Quality 

 II soils because of the thinnings may then be determined directly by 

 taking half the values deduced for thinnings and interest on Quality I 

 soils as shown in Table VII. Table VIII shows these amounts per acre 

 and the resulting amounts per M. ft. B. M. 



On Quality III Soil. The volume of the thinnings to be expected 

 from the Quality III soils may be determined by proportion just as they 

 were for the Quality II soils. In this case it would be as l6 l /2 is to 44. 

 As a matter of fact, however, the small sizes grown on Quality III soil 

 would greatly lessen the value of the yield from thinnings so that it may 

 be doubted whether this would exceed one-third of the value of Quality I. 

 Assuming it has one-third the value of the Quality I thinnings, the values 

 of thinnings per acre with interest thereon for Quality III may be taken 

 directly as one-third of the corresponding values in Table VII. 



TABLE VII. 

 Possible Deductions From Costs Due to Thinnings Douglas Fir Quality I Soil 



! 



ITEMS O 



Value of 30th year, thin- 

 ning 4 cords pulp- 

 wood at 50 cents per 

 cord $ 2.00 $ 2.00 $ 2.00 % 2.00 $ 2.00 $ 2.00 



Accumulated interest on 

 this value, 30th year to 

 60th year 2.84 4.48 5.48 6.64 9.48 13.22 



40th year thinning 5 cords 

 pulpwood worth $1 per 

 cord stumpage 5.00 5.00 5.00 5.00 5.00 5.00 



Accumulated interest for 20 



years 4.05 5.95 7.05 8.25 11.03 14.35 



50th year thinning 10 

 cords pulpwood worth 

 $1.00 per cord 10.00 10.00 10.00 10.00 10.00 10.00 



Accumulated interest for 10 



years 3.40 4.80 5.53 6.29 7.90 9.67 



Total amount saved per 

 acre when thinnings 

 are utilized $ 27.29 $ 32.23 $ 35.06 $ 38.18 $ 45.41 $ 54.24 



Amount saved per M. ft. B. 

 M. when final yield is 

 44 M. per acre * .62 $ .75 % .79 $ .87 $ 1.03 $ 1.23 



12 



