184 OUR FORESTS AND WOODLANDS 
they are finally suppressed in favour of the new 
crop about to be formed. This of itself unfits 
them for standards in copse, though otherwise 
their light overshadowing of the underwood 
would suit the position admirably— 
« And variable as the shade, 
By the light quivering aspen made.’ 
On highwood areas clear felled for regenera- 
tion, as sometimes happens with conifer crops, 
birch, aspen, and willow, the trees producing seed 
in largest quantities, and especially the former 
two, often spring up freely as self-sown seed- 
lings; and then they become weeds, difficult to 
exterminate owing to their strong reproductive 
power and to their rapid growth in height. 
Their removal, before regeneration is carried 
out on the neighbouring land, becomes a matter 
of necessity; while, if seedlings should obtain 
a foothold there, they must be cut out re- 
peatedly if necessary, otherwise the new crop of 
more valuable pine or larch will be interfered 
with and damaged by the less profitable soft- 
woods. 
As the seeds are light and filamented, they 
are easily borne by the winds into far-distant 
