116 Germany. 



be considered the foundation of the later develop- 

 ment by Carl Heyer (Felling budget = I + ). 



Based upon the normal forest idea, a number of 

 methods were elaborated which, because of their em- 

 ploying a mathematical formula for the determin- 

 ation of the felling budget, are known as formula 

 methods; they are, indeed modified rational volume 

 divisions. 



Hundeshagen has the merit of having first clearly 

 explained the basis of these methods, and himself 

 developed a formula, of the correctness of which he 

 was so convinced as to designate his method as "the 

 rational" one. Two other formulae were brought 

 into the world by Koenig (1838-1851), but the credit 

 of the most complete elaboration both of the principles 

 of the normal forest idea and of its practical applica- 

 tion belongs to Carl Heyer. The principles of his 

 method are briefly: First determine upon the period 

 of regulation during which the abnormal forest is 

 to be brought nearer to normal conditions; the length 

 of this period to be determined with due regard to 

 the financial requirements or ability of the owner and 

 to the conditions of the forest. The actual stock on 

 hand is then determined and the total increment, 

 based on the average increment at felling age of each 

 stand, which will take place during this period, is 

 added. Deducting from this total what has been 

 calculated as the proper normal stock requisite for 

 a sustained yield management, the balance is avail- 

 able for felling budgets which may be utilized in 

 annual or periodic instalments during the period of 



