90 THE THEORY AND PRACTICE OF WORKING PLANS 



and over diameter breast high, on looo acres. The mean annual 



increment equals .7 per cent, equals 24,500 feet board measure. 



The rotation is taken at 200 years. The normal growing stock 



, ri 200X24,500 , , • ^u r -. 



equals — = ^-^ — = 2,450,000 leet. v is, theretore, >nv 



2 2 



by 1,050,000 feet. This excess is, in view of local exigencies and 

 the wishes of the owner, to be distributed over - years = — - = 50 

 years = it;. By the formula: 



_7^+irt: — W2^_3,5oo,ooo+(24, 500X50) — 2,450,000 

 X 50 



3,Soo,ooo+i,2 2!:,ooo — 2,4c;o,ooo r . 1 , 



= '^-^ ^ ——^ = 45,500 feet board measure 



equals annual cut, which is exactly the same result secured by 

 the Austrian formula (No. 5) modified as suggested under 6, 



r \ . . , V — nV , S'SOO<000— 2,4^0,000 



(c). I.e., y = t-\ = 24,500 + ^-^^ ^ =45-500 



feet board measure. The only difference is if ix is modified 

 to correspond with expected changes during the next x years — ■ 

 as outhned above. 



(c) Value and Application. — Carl Heyer's formula dates 

 from 1841, and is perhaps the only one of the formula methods 

 in active use to-day. Gustav Heyer, in the revised edition 

 of Carl Heyer's work,* adds a complete period distribution of 

 the cut similar to that described under No. 17 below. However, 

 this is possible only under regular conditions and in even-aged 

 stands, and in no way destroys the effectiveness of Heyer's 

 formula in irregular, uneven-aged stands, although it correctly 

 emphasizes the importance of adding to the mere volume 

 determination of the cut a " when " and " where " by means 

 of a careful cutting plan (distribution of cut) as described below 

 in Section 2 of the present chapter. 



With this in mind, Heyer's formula is directly applicable to 



* Carl Heyer, " Die Waldertrags-Regelung," 1841. Second and third edi- 

 tions edited by Gustav Heyer, 1862 and 1883. 



