CHAP, ix.] Tending of Woods 203 



And Q = the cubic contents expected from mature crop after treatment 



by partial clearances, 

 V x = the value of same per load, or per cubic foot, at time of final 



clearance, 

 to. ---- t = outturn in cubic contents from partial clearances up till 



the harvesting of the crop, 



v a . . . . v$ = the sale-price of same per load, or per cubic foot, capi- 



talized until clearance of the mature crop takes place. 



When x is a minus quantity, then the method of partial clearance is 



remunerative, and therefore advisable. 

 x = o, then there is no financial advantage to be gained by partial 



clearances. 



x = a plus quantity, then the ordinary method of treatment by 

 thinnings merely is the more advantageous. 



But when underwood, which should almost always be 

 formed even on the better classes of soil can only be pro- 

 duced after a certain amount of outlay, then the complete 

 and correct formula for estimating the financial prospects of the 

 operations must be : 



CV + f a v a + 

 or, in another form similar to that originally given, 



Where /* = the outlay for producing underwood, capitalized until final 



clearance of the mature crop, 



and r the market value of the underwood at the time of clearance 

 of the mature crop. 



Practical experience in Germany has shown that this method 

 of partial clearance should, under ordinary circumstances, only 

 be adopted on the better classes of soil, and when undergrowth 

 can be formed either naturally or without any considerable 

 outlay. 



Pruning or Removal of Branches. 



High-forest crops, which have been properly tended and 

 thinned throughout the various stages of their growth, require, 



