Nature Bulletin No. 546-A   November 30, 1974
Forest Preserve District of Cook County
George W. Dunne, President
Roland F. Eisenbeis, Supt. of Conservation

****:THE OLIVE

Ages ago, in the crowded countries of the world, men turned to oil-
yielding plants for their fats. As America becomes more thickly 
populated and our fertile soils more scarce, we can be sure that our 
children and grandchildren will be eating less pork, beef and chicken. 
This is because several vegetarians can subsist on the grains and other 
plant products necessary to produce the meat that one average 
American now eats. Oils from corn, soybeans, peanuts, cottonseed and 
coconuts have already replaced most of the animal fats in our diet. But 
olive oil, that aristocrat of all edible oils, is also being imported by the 
millions of gallons for our fancy cooking and salads. Although a luxury 
item to present-day Americans, since ancient times it has been "the fat 
of the land" in the countries that border the Mediterranean.

Cultivation of the olive traces back beyond recorded history -- perhaps 
farther than any other tree. Its native home, the place where it was first 
domesticated, was probably on the limestone hills near the sea between 
Greece and Syria. The wild olive is a rather straggling small tree or 
bush with thorny branches. The cultivated varieties are more compact 
and less spiny with smooth leathery evergreen leaves, grayish-green 
above and whitish below. The olive does not begin to bear fruit until 
about twenty years of age; but this Methuselah among cultivated trees 
continues to yield, sometimes for hundreds of years. Old trees seldom 
exceed 30 feet in height, but the gnarled knotty trunk may be over 
twenty feet in circumference. The very hard wood with its beautiful 
grain and color is prized by cabinetmakers.

The olive is a stone fruit with the appearance of a purple plum when 
mature The oil, contained in the flesh, may make up as much as 60 
percent of the weight of the fully ripe fruit. The best quality, or rich 
yellow "virgin oil" used for salads, is made from hand-picked fruit 
which is carefully crushed and squeezed in presses. Speed is essential 
because the oil in bruised fruit quickly becomes rancid. Lower grades 
of oil are greenish in color and are used for cooking, in medicine, or for 
making Castile soap. A total of about one million tons of olive oil is 
produced in the world each year. Of this, Spain furnishes over 40 
percent, followed by Italy, Greece and Portugal.

Afresh olive picked off the tree, no matter how ripe, has a vile intensely 
bitter taste. In making pickled olives, either green or ripe, this flavor is 
removed by soaking them in weak lye. Then they are thoroughly 
washed, packed in bottles or cans (with or without pimiento stuffing) 
and sterilized.

When Thomas Jefferson was minister to France during the 
Revolutionary War, and continuing for the next 35 years, he imported 
olive trees and seeds many times in attempts to establish olive-growing 
in our southern states. At about the same time that Jefferson was failing 
because of the excessive humidity of the Carolinas and Georgia, the 
Spanish padres succeeded in the drier climate of southern California. 
There, olive culture did not spread far beyond the Franciscan missions 
until about 1890. However, by 1930, forty thousand acres were in olive 
orchards, mostly the Mission and Manzanillo varieties. During World 
War II, when imports were interrupted, this crop suddenly became very 
valuable. Some olives are also grown in Arizona and New Mexico. 
Now, the large amount of hand labor required for picking and 
processing makes it difficult for American growers to compete with 
imported pickles and oil.

Lilac, privet and ash trees are also members of the olive family.