Olive

From Freepedia

For alternate senses of this word see olive (disambiguation).

Olive

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Olea europaea (Olive), Lisboa, Portugal

Scientific classification

Kingdom:	Plantae
Division:	Magnoliophyta
Class:	Magnoliopsida
Order:	Lamiales
Family:	Oleaceae
Genus:	Olea
Species:	O. europaea

Binomial name

Olea europaea
L.

The Olive (Olea europaea) is a species of small tree in the family Oleaceae, native to coastal areas of the eastern Mediterranean region, from Syria and the maritime parts of Asia Minor. It is also thought to be indigenous in Greece. Olive trees shows a marked preference for calcareous soils and a partiality for the sea breeze, flourishing best on limestone slopes and crags.

The natural wild Olive is a small tree or shrub to 8 m tall with rather straggling growth and thorny branches. The leaves are opposite, oblong pointed, 4-10 cm long and 1-3 cm broad, dark greyish-green above and, in the young state, hoary beneath with whitish scales. The small white flowers, with four-cleft calyx and corolla, two stamens and bifid stigma, are borne generally on the last year's wood, in racemes springing from the axils of the leaves. The fruit in the wild plant is small drupe 1-2 cm long, and the fleshy pericarp, which gives the cultivated olive its economic value, is comparatively thin.

1 Cultivation and uses
2 Pests and diseases
3 See also
4 External links

Cultivation and uses

The Olive has been used since ancient times for the making of olive oil and for eating of the fruit, which, being bitter in its natural state, must be subjected to fermentation or cured with lye or brine to be made edible. It is often thought that this method of preparation was not developed until sometime late in the first millennium BCE although there may be some evidence for earlier consumption of olives (not just as oil) in the form of olive pits discarded in small camp fires at the Middle Bronze Age site of Ashkelon in modern Israel. Cultivated forms have wide variations in character, but are generally more compact, thornless, and more prolific.

It is not known when olives were first cultivated for harvest. Among the earliest evidence for the domestication of olives comes from the Chalcolithic Period archaeological site of Teleilat Ghassul in what is today modern Jordan. Olive stones as well as vats for crushing the olives into oil were found in an area where wild olives can still be found.

The plant is frequently referred to in the Bible and the earliest poets, to both the plant and its products. The ancient agriculturists believed that the Olive would not succeed if planted more than a short distance from the sea; Theophrastus gives 300 stadia (55.6 km) as the limit). Modern experience does not always confirm this, and, though showing a preference for the coast, it has long been grown further inland in some areas with suitable climates, particularly in the southwestern Mediterranean (Iberia, northwest Africa) where winters are less severe. Olives are now culivated in many regions of the world: in recent years Australia and New Zealand have started commercial production.

There is much research to support the health benefits of incorporating olive into the diet, a comprehensive review is to be found on the International Olive Oil Council website

Cultivars

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There are thousands of cultivars of the Olive. In Italy alone at least three hundred cultivars have been enumerated, but only a few are grown to a large extent. The main Italian cultivars are 'Leccino', 'Frantoio' and 'Carolea'. None of these can be safely identified with ancient descriptions, though it is not unlikely that some of the narrow-leaved cultivars that are most esteemed may be descendants of the Licinian olive. The broad-leaved olive trees of Portugal and Spain bear a larger fruit, but the pericarp has a more bitter flavour and the oil is of ranker quality. These Iberian olives are usually cured and eaten, often after being pitted, stuffed (with pickled pimento, onion, or other garnishes) and jarred in fresh brine.

Some particularly important cultivars of olive include:

Arbequina is a small, brown olive grown in Catalonia, Spain. As well as being used as a table olive, its oil is highly valued.
Empeltre is a medium sized, black olive grown in Spain. They are used both as a table olive and to produce a high quality olive oil.
Picholine originated in the south of France. It is green, medium size, and elongated. Their flavour is mild and nutty.
Lucques originated in the south of France. They are green, of a large size, and elongated. The bone has an arcuated shape. Their flavour is mild and nutty.

Growth and propagation

The olive tree, even when not pruned, is of very slow growth, but where allowed to develop naturally over many years, the trunk sometimes attains a considerable diameter. Augustin Pyrame de Candolle recorded one exceeding 10 m in girth, the age being supposed to amount to seven centuries. Some old Italian olives have been credited with an antiquity reaching back to the first years of the empire, or even to the days of republican Rome; but the age of such ancient trees is always doubtful during growth, and their identity with old descriptions still more difficult to establish. Cited before bishop Ludovico de Pennis' pastorale visit to Alliste on 11 May 1452 the Linza olive plants are of historical importance in Italy. In cultivation it rarely exceeds 15 m in height, and in France and Italy is generally confined to much more limited dimensions by frequent pruning. The wood, of a yellow or light greenish-brown hue, is often finely veined with a darker tint, and, being very hard and close-grained, is valued by the cabinetmaker and ornament turner.

The olive is propagated in various ways, but cuttings or layers are generally preferred; the tree roots in favourable soil almost as easily as the willow, and throws up suckers from the stump when cut down. Branches of various thickness are cut into lengths of about 1 m and planted deeply in manured ground, soon vegetate; shorter pieces are sometimes laid horizontally in shallow trenches, when, covered with a few cm of soil, they rapidly throw up sucker-like shoots. In Greece and the islands grafting the cultivated tree on the wild form is a common practice. In Italy embryonic buds, which form small swellings on the stems, are carefully excised and planted beneath the surface, where they grow readily, their buds soon forming a vigorous shoot.

Occasionally the larger boughs are marched, and young trees thus soon obtained. The olive is also sometimes raised from seed, the oily pericarp being first softened by slight rotting, or soaking in hot water or in an alkaline solution, to facilitate germination.

The olives in the East often receive little attention, the branches being allowed to grow freely and without curtailment by the pruning-knife; water, however, must be supplied in long droughts to ensure a crop; with this neglectful culture the trees bear abundantly only at intervals of three or four years; thus, although wild growth is favourable to the picturesque aspect of the plantation, it is not to be recommended on economic grounds. Where the olive is carefully cultivated, as in Languedoc and Provence, it is planted in rows at regular intervals, the distance between the trees varying in different olivettes, according to the cultivar grown. Careful pruning is practiced, the object being to preserve the flower-bearing shoots of the preceding year, while keeping the head of the tree low, so as to allow the easy gathering of the fruit; a dome or rounded form is generally the aim of the pruner.

The spaces between the trees are occasionally manured with manure or other nitrogenous fertiliser. Various annual crops are sometimes raised between the rows, and in Calabria wheat even is grown in this way; but the trees are better without any intermediate cropping. Latterly a dwarf cultivar, very prolific and with green fruit, has come into favour in certain localities, especially in America, where it is said to have produced a crop two or three seasons after planting. The ordinary kinds do not become profitable to the grower until from five to seven years after the cuttings are placed in the olive-ground. Apart from occasional damage by weather or organic foes, the olive crop is somewhat precarious even with the most careful cultivation, and the large untended trees so often seen in Spain and Italy do not yield that certain income to the peasant proprietor that some authors have attributed to them; the crop from these old trees is often enormous, but they seldom bear well two years in succession, and in many instances a large harvest can only be reckoned upon every sixth or seventh season.

A calcareous soil, however dry or poor, seems best adapted to its healthy development, though the tree will grow in any light soil, and even on clay if well drained; but, as remarked by Pliny, the plant is more liable to disease on rich soils, and the oil is inferior to the produce of the poorer and more rocky ground the species naturally affects.

Fruit harvest and processing

The ripe fruit is, by the careful grower, picked by hand and deposited in cloths or baskets for conveyance to the mill; but in many parts of Spain and Greece, and generally in Asia, the olives are beaten down by poles or by shaking the boughs, or even allowed to drop naturally, often lying on the ground until the convenience of the owner admits their removal; much of the inferior oil owes its bad quality to the carelessness of the proprietor of the trees. In southern Europe the olive harvest is in the winter months, continuing for several weeks, but the time varies in each country, and also with the season and the kinds cultivated.

The amount of oil contained in the fruit differs much in the various sorts; the pericarp usually yields from 60 to 70%.

Pests and diseases

The olive suffers greatly in some years from the attacks of various pests and diseases. A fungus Cycloconium oleaginum can infect the trees for several successive seasons, causing great damage to plantations. A species of bacterium, Pseudomonas savastanoi pv. savastanoi induces tumour growth in the shoots, and certain lepidopterous caterpillars feed on the leaves and flowers, while the main damage is made by the olive-fly attacks to the fruit. In France and north-central Italy olives suffer occasionally from frost; in the early part of the 18th century many trees were cut to the ground by a winter of exceptional severity. Gales and long-continued rains during the gathering season also cause damage.