Evening star. [volume] (Washington, D.C.) 1854-1972, 1883-02-17
Trees In City Streets.
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Geneva Letter to the London Times.
An Interesting controversy on the utility or
otherwise Of trees In streets and open spaces
has been lately going on here In the columns Of
the local press. The controversy arose out,of Q
discussion In the international Hygienic Con-
gress, which was held here In August, and DR..
Piachaud, q member Of the congress, has since
contended, in letter addressed to the Journal
de Geneue, that trees In streets do more harm
than good. that they impede the circulation Of
air. and that, as for the shade they afford, peo-
pie who do not like sunshine have only to keep
on the shady side Of the street. Instead Of
planting more trees in towns, as some propose,
he would rather in the interests of hygiene. re-
move all existing trees To him replies Prof.
Goret, OF the university, who, though an emf
nent physicist and chemist disclaims any special
knowledge of medicine or hygiene. He treats
the matter from al exclusively common
sense and scientific point of view. AS for people
who want shade keeping always to the shady
side OF the street, he points out that, as streets
have generally shops and houses on either side,
DR.. Piachaud's advice in this regard, however
ingenious, can hardly be regarded as practical.
But the functions of trees In streets are not
limited to acting as screens for sun-shunning
wayfarers; they temper the heat and serve as q
protection against dust. The evaporation from
the leaves tends to keep the surrounding air
cool and moist. One Of the best means of re-
freshng the air of a sick-chamber is to place in
1t plants and branches and sprinkle them with
water. A like effect is produced by trees.
Sunlight is necessary to health; but
trees, If not too thickly planted, do not inter-
cept sunlight; the perpetual vibration of their
leaves and swaying of their branches admit the
light every instant and in sufficient measure,
and serve. moreover, to protect the eyes from
the MONDAY glare So far from trees impeding
the circulation of air, they help to purify the
air; the evaporation from their leaves deter
mines current from above and the fresh air
thus brought down helps to drive away the
heated and dust impregnated gases of the
streets Another useful property of foliage is
that, while In hot, dry weather it moistens the
surrounding atmosphere, thereby rendering 1t
filter to breathe. this effect, which is due to
evaporation. ceases in wet weather. Trees.
moreover, act as purifying agents by absorbing
carbonic acid and giving out oxygen. But the
action of trees on the air is far less important
than their action on the soil. Their roots draw
up stagnant waters and absorb the organic mat
tiers contained in the filth from which the streets
OF the town are never free, and which,
after infltrating the ground, are frequent
cause OF fevers and infection. Trees, in fact,
have the same effect on the subsOiI of towns as
fields have on the contents of their sewers
they act as disinfectants. Taking these facts
into consideration Prof Goret ventures to differ
from the conclusions of the Hygienic Congress,
and strongly recommends the planting of trees
In streets and squares But they must be planted
with Judgment. They should be two or three
meters apart. and the branches should not be
allowed to come in contact with the buildings
near which they grow. The sorts best adapted
for street planting are those which grow to
considerable height and spread out their
branches. The fashion that prevails in some
continental cities Of cutting trees down to
uniform size is highly Objectionable. The
branches of trees so treated become impervious
to light, and the shade they give, although deep,
Is too cfrcumscribed to be of much use