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

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.

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