246 OUR FORESTS AND WOODLANDS 
soils suit it best, yet it grows well on any sort 
of dry land capable of being used agriculturally. 
On high situations with a light soil, however, 
the hedge can occasionally be much improved by 
mixing beech, or hornbeam (except on chalky 
soils), to the extent of about one-third along with 
the thorn, as apparently even here the soil- 
improving qualities of the dead beech-leaves, 
rich in potash, are of benefit to the quick. But 
the advantages of mixed crops, a sound principle 
for most kinds of woodlands, do not extend to 
hedges. The use of the shade-bearing beech and 
hornbeam is, however, often necessary to fill gaps 
in thorn hedges caused by rank growth of weeds. 
One decided drawback to this admixture of beech 
and hornbeam is, that cattle soon find out that 
these are not thorny, and then they often force 
their way through, undeterred by any fear of being 
torn or pricked. To make the hedge more of a 
fence, sweetbriar is often mixed with hawthorn ; 
but it soon spreads and interferes with the latter. 
Wherever the thorn thrives, as on heavy loams, 
it is certainly best to keep it pure and clean. On 
very light land, however, like most sands, or 
gravel, it is apt to die suddenly; and in such 
