TREES IN TOWNS 47 
a natural state, numerous species may be grown, if the 
smoke nuisance is slight. 
As regards planting in towns generally, the choice of 
trees should be restricted to really hardy species, which can 
live and thrive in the climate of the district, and which 
are capable of withstanding wind, if the situation is at all 
exposed. Species not liable to attacks of fungi and insects 
are also very desirable. The difference in the climatic 
requirements of trees is much greater than is generally 
supposed. For example, some American trees, like the 
black walnut and the tulip tree, which make noble specimens 
in the Thames valley and farther south, are often poor and 
stunted in the north of England and Scotland. The 
Chinese Paulownia imperialis, which is magnificent in Paris, 
is unlikely ever to succeed in any of our towns. New and 
rare trees, which may be seen flourishing at Kew, Glasnevin, 
and other botanic gardens, ought to be tried in town parks 
and spaces blessed with good soil, and not in streets, where 
all the conditions are unfavourable. 
Different species of trees vary much in the quantity and 
density of their foliage, and this affects their suitability for 
planting in streets. Some kinds, as the beech, carry a 
dense heavy crown of leaves, under whose shade nothing 
can grow. Trees of this class are not desirable in streets, 
as they keep the roads and pavements wet for long periods 
after rain, and prevent sunshine from reaching the houses 
in narrow streets. Other sorts of trees, of which birch and 
Robinia are good examples, bear light and sparse foliage, 
which casts little shade. Such trees are suitable for street 
planting. 
The size to which trees will grow in time is a matter of 
importance, as it is only in great wide streets that trees 
of the first magnitude can be safely planted. The form of 
trees must also be considered. In confined sites and narrow 
streets, trees of a columnar or narrow pyramidal habit are 
the most suitable. 
A few remarks on the species most suitable for towns 
will be useful. 
