THE NORMAL YIELD. 24-1 



Example : 



Area of forest . = 1000 acres 

 Rotation . . = 100 years 



1000 



Annual cutting area = - = 10 acres, 

 luu 



if the area is at once re-stocked. 



The annual yield of final returns, according to the table at 

 p. 190, amounts to 5580 + 286 per acre = 5866; for ten 

 acres = 5866 x 10 = 58,660 solid cubic feet. Final yield 

 during every period of 20 years = 58,660 x 20 = 1,173,200 cubic 

 feet. 



(2) Intermediate Yield. This consists of all the thinnings 

 which are made. Taking the same table, the following thin- 

 nings would be made in each year : 



In the coupe 30 years old = 10 acres, each giving 343 c = 3430 

 40 =10 614 c' = 6140 

 50 =10 572c' = 5720 

 60 =10 529c' = 5290 

 70 =10 443 c' = 4430 

 80 =10 386c' = 3860 

 90 . =10 828 c' = 3280 



Total = 32,150 



(3) Total Normal Annual Yield = 58,660+ 32,150 =90,810 

 cubic feet. 



b. Shelter-ivood Compartment System. 



The calculation of the yield is the same as under the system 

 of clear cutting, as long as the rotation r is maintained. If 



regeneration is commenced later than in the year r , the 



2 



rotation is increased, and the calculation must be made 

 accordingly. Supposing the first cutting is made in the year 



r, and the last in the year r+m, then the rotation =?*+ 



2 



A 

 and the mean annual cutting area = 



, m 



