AMONG THE OAKS 109 
The young trees should therefore be gradually 
accustomed to a larger growing-space, so that the 
crown of foliage of the tree may increase and 
form a greater quantity of wood year by year. 
Thenceforth, thinnings or partial clearances of 
the crop are necessary about every ten to fifteen 
or twenty years when the expanding crowns of 
the trees are found to interfere with each other. 
And when such operations are being carried out, 
the trees removed are of course those which show 
signs of disease, trees of other kinds, like ash or 
sycamore, which reach their full physical maturity 
at an earlier age than oak, and such oak as would 
prove least profitable if allowed to remain longer 
on the ground for the purpose of thickening into 
larger and more valuable stems. 
Up to this period in the cultivation of crops 
of oak timber, judicious thinning forms the best 
method of tending oak highwoods. With the 
exception of larch, no timber tree is so much as 
the oak dependent on thinning for its healthy 
growth and continuous development. The great 
golden rule for thinning, ‘Begin at an early 
period, carry it out moderately, and repeat the 
operation frequently,’ is one whose judicious appli- 
