40 



BRITISH FOREST TREES 



in height. An uninterrupted leaf-canopy stimulates growth 

 in height in such species as pines and most of the broad- 

 leaved deciduous trees, which tend to branch develop- 

 ment. Limitation of growing-space beyond the measure of 

 density necessary to maintain an unbroken canopy acts 



Feet 



Silver Fir.... / & V 



Spruce I& IV 



Scots Pino...- -I &- IV 



injuriously on the whole development, in place of stimulat- 

 ing beneficially to increased growth in height. 



(b) Growth in Girth is in all species of forest trees more 

 or less proportional to the growth in height, since the period 

 in which the latter is greatest is also nearly coincident with 

 that during which the trees are most active in increase of 

 girth ; in fact, the energy displayed in both of these directions 



