AUSTRIAN METHOD 



Yearly Cut = Yearly Growth -f- Actual Growing Stock Nor- 

 mal Growing Stock divided by an arbitrary period of years, or 



Ga Gn 

 Cut = Growth -J- 



a. 



Gr Gn 

 Also written : Y = Ir -\ -- ...... (Schlich).* 



ci 



Where Ir is Real or actual Growth or "increment", Gr is real or 

 actual Growing Stock and a is a period of years set arbitrarily in 

 keeping with conditions found on the property. 



The formula clearly shows the plan ; the surplus, or amount of 

 growing stock over and above normal, is divided by a and the I/a 

 part is added each year to estimated growth and is removed in 

 the cut. 



It also shows that if actual growing stock is deficient, as in 

 badly overcut forest properties, the quantity (Ga Gn)/a becomes 

 negative, and the I/a part of this deficiency, is deducted from the 

 estimated growth, the cut is lessened by this amount, and there is a 

 saving up of growing stock to restore it to a proper or normal 

 condition. 



To supply concrete illustrations for these methods using the 

 Growing Stock as a gauge in -Regulating the Cut, the following 

 premises are assumed : 



i. Actual Conditions of the Forest to be Regulated. 



AREA ACRES. AGE YEARS. STOCKED. 



7O TO O-9 



130 2O 0.7 



60 30 0.8 



200 40 0.7 



150 50 0.7 



40 60 0.8 



650 acres of woods. 



* In most books the Austrian Formula is written : 



Ga Gn 

 Cut = Growth -f- - 



which would assume that in the Austrian form it was prescribed that the 

 surplus must be spread over an entire rotation. And it is pointed out as a 

 special distinction of Heyer's formula to introduce a as an arbitrary period 

 in place of r or the rotation. Von Guttenberg declares this to be an error in 

 his book (p. 154) and his reasons are convincing. 



