72 FOREST VALUATION 



b. The irregular forest of many-aged stands requires a val- 

 uation from stand to stand and no general calculation can apply. 

 Such a forest can not possibly yield a uniform income, steadily until 

 it is changed by systematic regulation. In our wild woods the fol- 

 lowing three forms or conditions are common : 



1. The stand is generally mature, the merchantable timber 

 makes up seventy-five per cent and more of all growing stock. Such 

 stands have little value beyond that of the merchantable timber, for 

 usually the rest is stunted and is injured during the removal of the 

 old stuff. This, then, is a case of stumpage values. 



2. The stand is largely middle age stuff, which may be ex- 

 pected to be merchantable in a certain number of years, as seen by 

 growth studies. Here it is simply a case of m Ge, as developed 

 before. 



3. The stand is mostly young stuff, such as reproduction on 

 burns, windfall, etc. In these cases the cost value, m Gc, should pre- 

 vail. Where such reproduction comes in with open, mature, or over 

 mature stands, the area of the young stand is estimated; its cost 

 value and the stumpage value of the old stuff are determined sep- 

 arately. 



