VOI..U M F, AU.OTM KNT 1 47 



1. On a property of 20,000 acres of forest it is utterly impos- 

 sible to measure accurately the amount of growth. And herein lies 

 the weakness of all Regulation by Volume. In area regulation 

 quantities are exactly known, if rotation is eighty years, the forester 

 knows that a normal cut is 20000/80 = 250 acres. Volume Regula- 

 tion, on the other hand, is fortunate if Growing Stock is known 

 within 15%, and as to the growth, it can only be inferred from a 

 comparison to known conditions (Yield Tables) or from stump- and 

 stem-analyses and an estimate of how far these analyses apply in 

 the actual Stand. In well regulated forests of Spruce in Saxony 

 these estimates are amply reliable, in wild woods they rarely are. 



2. For these reasons Volume Regulation is never more than an 

 initial step and has given way to area regulation wherever forestry 

 has made real progress. 



But as a beginning it has value, and this is especially true under 

 conditions where only portions of the forest have any market at all, 

 and where large areas are in a formative state, of great and certain 

 value in the near future and yet of no sale value at the present time. 



3. When Regulation has decided the Volume which may be cut, 

 say 15,000 cords from 20,000 acres, it has done practically all that 

 Method of Regulation of the Cut can do and the rest is a matter of 

 proper distribution, i. e., what stands to cut, and of silviculture. 

 For this reason most Volume methods attempt only to estimate the 

 amount of timber to be cut. 



i. Volume Allotment. 



The following case illustrates this method : 

 a. Plan for 1914-1933. 

 Area of forest 20,000 acres. 

 Species : Pine. 



System : Clear Cut and Plant. 

 Rotation : 80 years, hence 4 age classes. 



Site I 20% of area, yield at 80 years 7000 cu. ft. per acre. 

 Site II 50% of area, yield at 80 years 5600 cu. ft. per acre. 

 Site III 30% of area, yield at 80 years 4200 cu. ft. per acre. 

 All areas to be ''reduced on plan : 



Site I acre =i}4 acre "reduced" area. 

 Site II acre = i acre "reduced" area. 

 Site III acre = 1/4 acre "reduced" area. 



