66 
TREES AS GOOD CITIZENS 
them is with branches resting on the ground, and the 
removal of these destroys the beauty of the tree. More¬ 
over, they will not withstand the soot and dust and sul¬ 
phur fumes prevalent in a city. 
Hackberry. —Because of its ability to thrive in 
poor soil and in varying cli¬ 
mates, the Hackberry has 
staunch friends among the 
planters of street shade 
trees, especially in the south. 
It is valuable in the western 
half of the country, but in 
the east it is rather ragged. 
In appearance, it is much 
like the Elm, although smal¬ 
ler and more erect. The tree 
is affected in someplaces bya disease called Witches’Broom. 
Ailanthus or Tree of Heaven. —The chief recommen¬ 
dation for this tree for street planting is that it will 
thrive where others would die. The poorest soil and 
the most forbidding environment seem to offer no dis¬ 
couragement to it. Its growth is very rapid and, in its 
younger years, it has attractive form, which it maintains 
with advancing age if not 
mutilated by accident or 
severe pruning. It is useful 
where other trees would not 
grow, especially in the heart 
of cities, and for this reason 
should have its place among 
trees to be considered for 
congested areas. The foliage 
is rich and heavy and prod¬ 
uces good shade. Because 
