114 
ARTIFICIAL ADAPTATIONS OF 
high rural tastes of the people continue to produce their greatest 
variety and perfection. With us they are never likely to be used 
to so great an extent for fences owing to the cost of maintaining 
them ; but as ornamental and useful screens, and for other deco¬ 
rative purposes, there need be no limit to their variety. For these 
purposes some of the evergreens are best. 
The arbor-vitaes are peculiarly adapted for hedges and screens; 
especially for those of medium height, which are not intended to 
turn animals. The species and varieties of arbor-vitae are numer¬ 
ous, but it is doubtful if there is one among them all more valuable 
for this purpose than the indigenous American species which is 
found wild on the banks of the Hudson, and other eastern rivers ; 
though it is claimed for the Siberian arbor-vitae, and with truth, that 
its foliage has a richer shade of green. 
There is a material difference in the value of different 
forms for hedges; and the kind of tree used, the purpose 
for which the hedge is intended, and the exposure it is to 
have, must influence the choice of one form rather than 
another. 
Fig. 22 represents a hedge-plant of the arbor-vitae as 
grown, say the third year after planting. It must now 
be decided what form the hedge is to have. Fig. 23 is a section 
of the most common, and, for the arbor-vitae and hemlock, in open 
exposures, a good form. But it is evi¬ 
dent that a hedge of this form gets Fig - 2 4 - 
less sun at the bottom than near the 
top, and the natural result is to pro¬ 
duce the weakest growth at the 
bottom, and finally that the lowest 
branches die out. The shaded parts 
of hemlocks, if contiguous to moisture, do not seem to suffer for 
want of the direct rays of the sun, but a majority of hedge- 
plants need a full and even light upon them. It is not merely the 
direct rays of the sun which are essential, but that constant light 
from the sky which, with or without the sun, always rests upon 
the top of a hedge. If the top be broad as in Fig. 24, it 
receives nearly all the direct light from above, and shades the 
Fig. 22. 
