70 FOREST VALUATION 



necessary to keep in mind that this simple formula depends on sub- 

 stituting Se for other values of soil, Sc or Ss. 



c. Cost value of the growing stock of a regulated forest. 



In this case the value of the growing stock of the ten-acre sam- 

 ple is obtained by adding the values of the ten acres, writing the 

 value of each by the general formula as developed before : 



Sc) (i.op"'_i)_Ta(i.op m - a ) 



where again m is the age of any one stand. 

 i. This leads to the formula: 



c per acre= 



2. To illustrate: forest of 16,000 acres, clear cut, and plant; 

 rotation, 80 years ; p, 2% ; premises per acre : 



Cost value of land, $10. 

 Cost of planting, $10. 

 Current expense, $1.50, hence E, $75. 

 Thinning at 20 years, no income. 

 Thinning at 40 years. $10. 

 Thinning at 60 years, $20. 

 Then the average cost value of growing stock per acre : 



(10 + 75 + ICO (1.02 s0 l) 10(1.02* l) 20(l.02 2 l) , 



80(1.02-1) -(75 + 10)= $131 



and for 16,000 acres about $2,096,000. 



3. Simplification of this formula by substituting Se(i.op r i) 

 for Sc(i.op r i) results in the same form found for ' (r ' T) Ge so 

 that: 



when Se is employed as the value of the land in place of Sc, or Ss. 



H. VALUE OF THE GROWING STOCK IN THE ALL- 

 AGED OR MANY-AGED FOREST. 



Two cases arise : the regulated and the irregular forest. 



a. The stand is truly all-aged and regular as in the case of a 

 well managed selection forest. Here old and young are in proper 

 proportion, all age classes are represented and occupy equal areas. 

 The difference between the growing stock of this forest and that 

 of a forest of even aged stands is merely in the distribution of old 



