The weekly democratic statesman. [volume] (Austin, Tex.) 1871-1883, 1882-03-09
shade Tree. Promotive OF Health.

The usual object in Sc ting shade
trees is to secure their pleasant
shade and to ornament the grounds.
They have value, however, far
greater than this. They are efficient
promoters of health. He who sets
shade trees about his buildings not
only adds the most alluring orna-
ments, but also hedges his family
about with the most efficient pro-
tectors of their health. 1t is not in
tended to claim that shade trees will
prevent all kinds of disease, but
merely that in certain ways they aid
materially in preserving the health.
Trees act in several ways in pro-
noting health. They improve the
drainage aud render the soil less
damp. Dampness is one of the most
common causes of ill health, and
is promotive of rheumatism, neural
gia, consumption, catarrh and vari-
Gus diseases. Dampness promotes
the decay of filth and the genera
JiOn of noXious and disease gener-
ating gases. 1t predisposes the sys-
tenn to various diseases, and needs
to be carefully guarded against.
Trees, if properly placed about the
building will diminish the damp.
ness arising from the soil. If the
trees are placed too near the house
they will keep out the rays of the
sun and prevent the free circulation
of air, and thus increase the damp
ness within the house. To obtain
the best effects, they should be set
at such distance from the house as
to allow free access of the rays OF
the sun and free circulation of the
placed, the trees penetrate with their
roots through the soil deep into the
subsoil, extending in every direction.
Wherever a root penetrates the sub
soil, a way is opened through which
the water on the surface sail can
find its way to the earth beneath, in
stead of being held in stagnant ac-
cumulations on the soil, as is often
the case. Where there is an imper-
vious subsoil, the effect of trees in
improving the drainage and dimin-
ishing the dampness is very well
marked. There is another way in
which trees improve the drainage.
They draw up continually large
quantities of water, in the form of
sap, which passes into the leaves
and is evaporated. The amount of
water thus removed daily from the
soil by one large tree, with
foliage sufficient to cover three
or four acres of surface,
is considerable. and when there are
several the effect would be pro-
portiOnately greater. This effect of
trees in rendering the soil and SUBJ
soil more easily penetrated by
water, and the removal of consider
able water in the form of sap, ma
terially improves the sanitary con-
dition, and prevents many evils
arising from stagnant water. A
more important service performed
by trees is the removal of filth. The
soil around buildings contains more
or less filth. In some places the soil
is saturated with it, and when the
weather is warm, hurtful emana-
tions are sent up from this decaying
filth. Shade trees flourish in just
such filthy places. The filth
furnishes them abundant food,
and is rapidly taken up
with the sap, and promotes the
growth of the tree. A few trees
planted at the terminus of sink
spouts will naturally assist in re-
moving the filth and keeping the
air pure. The roots absorb large
quantities of the liquid filth, and the
leaves take up some of the noXious
emanations and destroy others. The
most important sanitary service per-
formed by trees is the purifying eff
feet which they exert on the air.
The air is constantly becoming
charged with carbonic acid pro-
duced by the combustion of wood
and coal, by the decay of animal
and vegetable substances. and given
off from the lungs of animals. This
carbonic acid gas is poison to man
and other animals, but is food for
trees and plants, and is absorbed by
their roots. The leaves absorb car
bonic acid and give out in return
oxygen, which is powerful agent
in purifying the air by oxidizing or
burning up deleterious substances.
Oxygen is also the substance re-
moved from the air during the pro-
cess of breathing by man and ami
mails, and is necessary to the
maintenance of life. Plants and
animals evidently were designed to
thrive side by side. The substances
thrown off from the lungs of ami
mails furnish food for plants, and
the oxygen given on. by the leaves
of plants is just what is required to
purify the blood of man and ami
mails. Where the habitations of
men are most thickly placed, there
the need of trees and plants is most
needed to purify the air, yet there
they are fewest in number. Not
only do trees remove carbOnic acid
from the air but they also remove
poisonous miasms. In the malarious
regions of the west, it is some times
noticed that the Intervention of a
belt of forest trees prevents the
sprea d of malaria in that direction.
At Pulo, a railroad station near
Rome, in Italy, piece of woods had
stood for many years between the
settlement and malarious district
to the south, and the inhabitants
were free from malarious diseases.
Finally the trees were cut down, and
then malarious diseases became pre-
valent. Manziana, Italy, was almost
wholly free from malarious diseases
until the shepherds, by setting fire
to it, destroyed the adjacent olive
forest, after which malarious dis
eases became prevalent. Lancisci
relates that the insalubrity of Rome
was notably increased in the days of
Gregory XIII by the destruction of
a forest which was infested with
brigands. The abbey of the Three
Fountains, near Rome, which for q
long time had been regarded as one
of the most insalubrious and fever
breeding places in all the campagna,
was decidedly improved by having
a plantation of eucalyptus trees sci
out. In Algeria, the pestilentlal
emanations from marshes arc
counteracted by planting eucalyp.
tus trees. 1t is supposed that
those trees protect, partly by alb,
sorblng moisture from the soil, and
partly through the complicated ex
halations from their leaves, which
purify the air. Some have attrib
uted the purifying effect exerted by
trees upon the air to ozone, which is
found in the air near trees. Ozon,
is a name applied to oxygen whel
il is in a highly electrified condition