THE THEORY AND PRACTICE OF WORKING PLANS 7 



timber, but it may also be used with reference to the density 

 of stocking, age classes, etc. 



The normal growing stock (nv) is theoretically attained 

 from normal age classes and normal increment, practically it 

 results from normal age classes and actual increment. 



The actual growing stock (v) is that which is present on a 

 given forest. This is obtained by timber estimating. 



The normal growing stock (nv) is obtained (i) by formula, 

 (2) from yield tables. 



Diagram B 

 A, 1 1 I r- ^ ^ , < ^ , , , , ^B 



10 20 30 10 50 60 70 80 90 100 110 120 130 110 

 Age ia Years 



(i) The normal growing stock is expressed by the formula: 



where W2) = normal volume of growing stock, ;- = rotation, and 

 ^ = the mean annual increment. 



(2) nv can also be determined directly from yield tables 

 constructed by measurements of fully stocked stands. 



m\ 



nv then 



equals nia 



+&+C . . . + 



