THE THEORY AND PRACTICE OF WORKING PLANS 109 



cutting area reduced to terms of Site Quality I equals 130 acres. 



The stands ripe for cutting in the next twenty years (oldest 



age class) show an average stocking of .7 and an average site 



quality II, and hence (from yield tables or from measurements 



of sample plots of mature fully stocked stands of varying site 



qualities) an average volume of 46, 900 X.7 =32,830 feet board 



measure per acre. 130 acres are to be cut per annum. This 



is equivalent (see example method No. i, Var. II) to 166 acres 



of site quality II. Hence the annual cut = 32,830X166 = 



5,449,780 feet board measure. 



Variation III. Hufnagl. Using the figures in the example 



under method No. i : 



1) 

 The volume of the annual cut = -X29. 



a 



(c) Value and Application. — As noted under similar heading 

 in method No. i, the method has all the disadvantages of a fixed 

 value for the rotation, instead of a naturally adjustable one, 

 and allows none of the free play so necessary for the best silvi- 

 culture. Variations I and III are exceedingly simple, and 

 hence quite well adapted to forests with fairly uniform conditions, 

 i.e., coppice and coppice with standards. Variation II is too 

 complex for all but the most intensive conditions, and requires 

 all the data, while possessing none of the advantages of other 

 and better methods. Obviously the method presupposes an 

 age-class table, and hence a forest composed of fairly even- 

 aged stands. It is therefore essentially not a method for selec- 

 tion forests.* Its chief use is as an area check on the figures 

 obtained by other methods. 



* In selection forest the area-volume calculation, as stated under Method 



No. I, is based on the cutting cycle and not on the rotation. It may be expressed 



total area 



as a formula: annual cut = X amount to be removed per acre. In 



cc 



this form it is useful as an area check on other methods of calculating the cut in 



selection forests. 



