The Cork Oak in the United States 
By Victor A. Ryan, Director of Research, Crown Cork and Seal Company, Inc., 
and Gites B. Cooke, Director of McManus Cork Project, Research Department, 
Crown Cork and Seal Company, Inc., Baltimore, Md. 
[With 8 plates] 
The cork tree is a species of oak 
which is known botanically as Quercus 
suber. The wood is light in color and 
the cork oak has been considered to be 
of the white oak variety. Recently 
Williams (1) } has shown the wood of 
the cork tree possesses grain structure 
similar to that of the red oak. 
Cork is the bark of the cork oak tree 
which is native to the small area that 
forms the shores of the western Medi- 
terranean. When the tree is 20 years 
old or about 9 inches in diameter, cork 
is stripped from the trunk. New cork 
grows to replace that removed, but 
much faster than the original bark, 
and subsequent strippings of the cork 
tree are made every 8 to 10 years. 
The bark after being boiled, scraped, 
dried, and baled is the cork of com- 
merce. For more than 2,300 years 
the world’s supply of cork has come 
from Europe and North Africa. 
The United States uses more cork 
than any other country. Cork is very 
important to our national economy, 
for it is both a critical war material 
and an essential peacetime commodity. 
To meet this Nation’s manufacturing 
requirements approximately 160,000 
tons of corkwood are imported annu- 
ally. From this cork many important 
articles are produced. These include 
bottle stoppers, life preservers, ring 
buoys, floats, shoe inner soles, sealing 
1 Numbers in parentheses indicate refer- 
ences at the end of this article. 
liners for bottle caps, gaskets of many 
types for automobiles, electric motors, 
switch boxes, household appliances 
and other articles, friction rolls, polish- 
ing wheels, and corkboard for insula- 
tion, acoustical and machinery isola- 
tion purposes. 
Early Plantings in the United States 
The founders of our country were 
aware of the importance of cork. At 
the same time they knew the cork tree 
could be grown in the South and pos- 
sibly elsewhere in the United States. 
As early as 1787 Thomas Jefferson sent 
cork acorns from France to William 
Drayton of ‘‘Magnolia”’ at Charleston, 
S.C. No cork trees resulted from this 
planting, but Thomas Jefferson con- 
tinued to recommend and urge the 
planting of cork trees until his death 
in 1826. 
While the records indicate no cork 
trees were established by Thomas 
Jefferson, his efforts to introduce this 
tree in the United States were not in 
vain. Interest in the cork oak had 
been aroused, and in 1858 the Federal 
Government obtained cork acorns 
from Spain and distributed them in 
the South and in California. Some 
trees were obtained from this planting, 
but many of them were lost through 
lack of care, drought, and other causes. 
Again in 1880 cork acorns were im- 
ported, and a few additional cork 
trees were obtained. In 1914 the 
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