AMONG THE OAKS 97 
There is, however, a limit to this forcing of 
the oak in restricting its natural tendency 
towards branching habit of growth, with a view 
to the development of a long, clean bole. With 
the oak, as with all the other forest trees, the 
manner in which this treatment may be practised 
depends not only upon a variety of physical 
conditions relating to the given soil and situa~ 
tion, but also upon certain specific natural re- 
quirements regarding a sufficient space for the 
growth of each individual tree; and these latter 
characteristics show themselves in a very marked 
degree, either in a strong demand for light or in 
a certain capacity for bearing shade. 
In dealing with any kind of tree grown as a 
timber crop, control over the tendency to the 
formation of large branches can only be exerted 
so long as the vegetative energy can be trans- 
formed from impulse towards lateral extension 
into growth upwards. So long as a rather close 
condition of crop results in good growth in height, 
this is more advantageous than branch develop- 
ment; but when the former has reached its maxi- 
mum and shows signs of diminishing, it is then 
time to thin lightly, so as to allow the remaining 
G 
