VOLUME INCREMENT. 



175 



part of the tree ; hence, the forester is specially interested in 

 the height and diameter growth. 



It has been explained in Volume II. of this Manual, third 

 edition, p. 54, that the energy of height growth differs not 

 only according to species, but also, in the case of one and the 

 same species, according to the age of the tree, the productive 

 power of the locality and the method of treatment ; besides, 

 there is in this respect a great difference between seedlings 

 and coppice shoots. 



The subjoined table exhibits the height growth for some 



of the more important species of Europe, taking in each 

 case a locality of good productive power and assuming, that 

 the trees have grown up in fully stocked woods (see Fig. 40). 

 The height growth of oak is similar to that of beech. It is 

 somewhat quicker during the first few years; later on oak 

 holds its own against beech in some localities, and it is 

 passed by it in others. 



Generally speaking, in the case of aeedlings, the height 

 growth during earliest youth is, in temperate climates, com- 

 paratively slow ; it then increases rapidly, remains steady for 

 a time, then decreases and ceases altogether, or nearly so. 



The periods, when the current annual and mean annual 

 height increment show their maxima, are of special interest 



