2i 8 Studies in Forestry [CHAP. x. 



cient extent, these portions of the lower foliage, which have 

 been practically inactive, or may perhaps even have been 

 existing on the work done by the upper leaves or needles, 

 reassume their normal assimilative functions and help to 

 enhance the general increment of the tree. And, besides this 

 increased assimilative power of the foliage, the consequent 

 increased formation of new leaves and needles is undoubtedly 

 of enormous influence in maintaining and increasing the 

 general enhancement of increment throughout the stem. As 

 remarked by Konig 1 , the direct result of the freer exposure 

 to light and warmth leads to the better and more energetic 

 development of the leading-shoots, the strengthening of twigs, 

 and the formation of twigs from buds that would otherwise 

 most probably have remained dormant. 



The enhanced increment continues until the crop once 

 more forms close canopy. But, if it be again stimulated by 

 a repetition of the thinning out or partial clearance, this may 

 if not accompanied by underplanting be carried so far as to 

 involve deterioration of the soil to such an extent that the 

 beneficial influence of light and warmth on the crown is 

 cancelled by the diminished activity of the root-system, con- 

 sequently involving decreased supplies of moisture and of 

 mineral nutrients for conveyance to the assimilative organs. 



The simultaneous underplanting of crops subjected to this 

 system of partial clearance, and especially of those of light- 

 demanding kinds of trees Oak, Ash, Maple, Larch, and Scots 

 Pine has an undoubtedly stimulating result in effecting and 

 maintaining the enhancement of increment after partial 

 clearance, and is of particular interest from the financial point 

 of view. The influences exerted by the soil, the situation, and 

 the age of the crop, exhibit themselves rather with regard to 

 the extent of the enhancement in increment than to its 

 production and continuance. Unless the individual trees are 



1 Ueber Lichtungszuwachs, insbesondere der Buche, 1886, p. 7. 



