50 FORESTS, WOODS, AND TREES 
fastigiate form of the white poplar, resembling the Lombardy 
poplar in shape, but distinctly wider with less upright 
branches, has been recommended for streets; but I have 
never seen it used. It should be tried as it is a beautiful 
tree in habit and shape, and succeeds well in Kew Gardens. 
It would probably thrive in the north, as it comes originally 
from Turkestan, where the winters are extremely severe. 
The balsam poplar, with balsamic odour of foliage and buds, 
occasionally seen in London streets, is Populus candicans, 
a female tree of unknown origin. It bears smoke well, but 
is unsuitable for streets, as its suckers come up freely through 
ordinary pavements. 
Ailanthus glandulosa, a native of China, is a fine tree 
with magnificent pinnate foliage, which thrives and bears 
smoke well in towns in the south of England. It does not 
succeed, however, in Scotland or Ireland, where there is 
not enough heat in summer for the well-being of this 
species. 
Robinia Pseudacacia, an American tree, commonly but 
erroneously called ‘ Acacia,’ is a successful street tree, very 
desirable on account of its pure white flowers and graceful 
foliage, the latter remaining fresh and green even in the 
driest summer. It suffers, however, much from wind, and 
in Ireland, Scotland, and the west of England and Wales 
should not be planted except in warm sheltered situations. 
A form of this tree, known as var. Decaisneana, which pro- 
duces handsome pink flowers, and appears to be more 
vigorous than the type, is well worth planting as a street 
tree. Var. pyramidalis resembles the Lombardy poplar in 
shape, and is also suitable for streets. 
The common ash, Fraxinus excelsior, thrives fairly well 
in parks in London and other cities; but it is unsuitable 
for planting in streets, as its foliage is both late in coming 
out in the spring and early in falling in autumn. It takes 
up a great deal of space, and has wide-spreading roots, so 
that shrubs and other trees do not flourish in its immediate 
vicinity; and on this account it is not fit for town gardens. 
Two of its varieties, the weeping ash (var. pendula) and the 
