THE SOFTWOODS 183 
remarkable degree among all the other light- 
demanding trees, the two characteristics of rapi- 
dity in growth upwards and thinness of foliage. 
Their hardiness against frost, their rapidity in 
growth, and the comparative lightness of the 
shadow they cast around them, qualify them 
excellently, and especially the birch, for acting 
as a nurse to species like oak, ash, chestnut, beech, 
&c., in places where they are likely to be 
nipped and damaged by late frosts in spring. 
When once these kindly offices have been per- 
formed, however, birch and. aspen should be 
at once cut out, else they only interfere with 
the growth and the healthy normal development 
of the more valuable young trees desired as the 
crop. Even then much trouble is often caused 
by the stool-shoots of the birch and the suckers 
thrown up in profusion by the aspen, as both 
trees are strongly reproductive when thus felled. 
It is often wonderful how long a hold on life 
the roots of aspen seem to have; for the suckers 
often spring up very freely when mature crops 
of timber are being felled, even though it be 
long years since the aspen have been cut out. 
And such stoles can prove noxious weeds before 
