Evening star. [volume] (Washington, D.C.) 1854-1972, 1927-06-25
CORK PRODUCERS
AIDED BY SCIENCE
Industry Relieved as New
Uses Are Found for Bark
in America.

Spanish cork producers are learning
with relief that progress and science
often find new uses for old products
when old uses are passing into the
discard. They saw a marked slump
in the demand for bottle shoppers a
few years ago. especially in America,
where the crimped metal cap with
only a thin lining Of cork has be-
come the standby of. the soft-drink
industry. Cork prices dropped and
producers saw ruin ahead.
Now, thanks to the growing use OF
cork in America in thousands OF
household refrigerating machines,
radio instruments. and electrical de-
vices, Spain has had her most pros
porous cork year. A bulletin from the
National Geographic Society tells Of
cork production.
Trees "Skinned Alive"
1.-THE cork industry depends on the
peeling of bark from living trees"
says the bulletin. THE trees are a
species of evergreen oak. They are
literally skinned alive yet they have
the valuable ability not only to con-
tinue to live, but to set about inl-
mediately to grow new and better
bark.
Spain is probably the best known
source of cork, yet it is not the great
est cork.growing country. Portugal.
with approximately a million and a
half acres of cork groves, has twice
the area devoted to cork growing by
her eastern neighbor. North Africa
also is an important factor in the
growth of the bark. Algiers has
nearly a million acres in cork oaks
and Tunis about a quarter million
acres. Small quantities are grown
also in southern France and Italy.
But in the actual production OF
cork for the market Spain and Por-
tugal lead. These two countries
have exported tr,yether recently
about $1s,OO0,0O0 worth Of cork and
cork products annually. OF this
Spain ships the greater share, meas
ured by value, since nearly all Span
ish shipments are of manufactured
products, while Portugal exports
mostly crude cork. Close to s6,O0O,-
600 worth of cork Is imported into
the United States annually. The
other principal users are Great Brit
ain, France and Germany.
Eight Years Between Harvests.
There are few crops for which
one has to wait longer than for cork.
If the best practice is followed, trees
are not given their first stripping un.
til they are 20 years old. This first
crop is coarse and practically worth
less. 1t is used chiefly as a source
of tannin and to make rough bark
baskets for ferns and the like. The
owner of a cork oak grove must walt
or 8 years after the first stripping
for his second harvest of cork. This
second crop Is better than the first,
but is still considered of poor quality.
There must be an interval of bark
growth of s or 9 years between all
succeeding harvests.
Meanwhile, the quality of the cork
is steadily improving. If the bark Is
removed carefully so that the under
lying tissue is not injured the trees
thrive and continue to produce their
harvest until they are $50 years old
or more.
when the bark comes from the
trees, it is in trough-shaped pieces
| "a. to 2h inches thick and several feet
long. After drying for few days the
pieces are boiled in water and weight.
ed down until they assume a fiat
shape. These fiat slabs are baled and
shipped from the country or sent to
domestic factories.
Has Variety Of Uses.
Cork is best known in the form Of
bottle shoppers. 1t was used by the
Romans to plug wine containers.
When glass bottles came into general
use during the fifteenth and sixteenth
centuries, the cork stopper industry
grew to Importance. This primary use
continues, but many new uses have
been added. Today cork is made into
floats for fishing nets and lines and
into washers and insulators for vari.
Gus devices.
ut Is used in life preservers, re-
frigerators, artificial limbs, hat Innings
and as inner soles for shoes. Glass In
polished with 1t; cut to paper thinness,
1t Is made into cigarette tips, and,
ground, the coarser grades are used as
a packing for china and for fresh fruit.
A growing u>e in recent years has
been as an ingredient for the manu-.
facture of linoleum. Cork is ground
very fine for this purpose, and the
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