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CHAPTER I. 



THE INCREMENT. 



Every tree or wood may lay on three different kinds of 



increment, namely : — 



(1.) Quantity or volume increment. 



(2.) Quality increment.) ,, ,, w, , • . 



^ . . >Also called the value nicrement. 



(3.) Price increment. ) 



Section I. — Volume Increment. 



By volume increment is understood the increase in the 

 volume caused hy the growth of a tree or a wood. It is 

 measured by the solid cubic foot, or the stacked cubic foot. 

 The different kinds of volume increment and the modes of 

 measuring them, have been explained in Forest Mensuration. 

 For the purpose of working plans, it must be added, that 

 for short periods, say 5-10 years, the periodic mean annual 

 increment can be put equal to the current annual increment 

 without any appreciable error. 



The calculations of increment may refer to the final yield 

 only, or to the intermediate yields, or to both together. In the 

 tables in Appendix III., the various classes of increment 

 have been calculated separately for final, intermediate and 

 both yields together. 



1. Pror/fc'ss of Volume Increment. 



a. Of Single Trees. 



The volume increment is produced by an annual extension 



of the crown and roots, and by the addition of a new layer 



between wood and bark all over the stem, branches and roots. 



As a general rule, the stem, or trunk, is the most important 



