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Olive Tree Garden


See a century old olive tree in a water smart garden for both children and adults. Located by Hamilton Children’s Garden.

Ancient Olive Tree

A nice outcome to being a part of the San Diego County Fair was the donation of a 100 year-old Sevillano olive tree by Aaron Mount of Ancient Olive Trees in 2008. This gorgeous specimen was part of the award-winning Falling Waters exhibit designed by Ryan Prange for the Fair. It is a choice specimen in our Mediterranean Garden that will link California Gardenscapes with the Hamilton Children’s Garden.

The Olive Alone

By Dr. Ori Fragman-Sapir
Jerusalem Botanic Gardens
Translation by Susan Hattis Rolef

Note: The Jerusalem Botanic Gardens (JBG), located in Israel, is a sister garden to the San Diego Botanic Garden. Dr. Fragman-Sapir is the Director of Research and Conservation at JBG.

Olive Tree

Julian Duval, SDBG President and CEO with a wild olive tree in Israel.

The Common European Olive (Olea europaea) is a Mediterranean, evergreen tree, which grows in Israel in the wild, as well as, and especially in orchards around the Mediterranean Basin and beyond. The oldest olive finding that was discovered in Israel, in the archeological digs in the Oren Stream on Mount Carmel, in the form of olive pits, which were dated at around 10,000 BCE, suggesting that prehistoric man fed on olives. The domestication of the tree occurred around the year 4,000 BCE. Today the olive in primarily a cultivated tree in Israel, and most of the olive trees to the length of Israel are planted, or the seedlings of cultivated trees that germinated in deserted terraces and other habitats. Real native wild olives may be found in Israel only on Mount Carmel and the Western Galilee. These are shrubby olive, with smaller fruit.

As already mentioned, the Common European Olive is common around the Mediterranean Basin, but an examination of the olives along Africa reveals that it exists on cliffs from Mediterranean North Africa to South Africa. The South African entity – the Wild African Olive (Olea africana or Olea europaea ssp. cuspidata) – is characterized by extremely small fruit, and frequently by golden rather than silvery leaves. Between the European Olive and the African Olive one can see intermediate fertile forms, which are considered a single species with many varieties. The Wild African Olive can be seen in the South Africa Section in the Jerusalem Botanical Garden, where we can compare it with the Common European Olive. Additional species of olives are various tropical species that grow in the forests of Africa and Southern Asia. These suggest the tropical origin of the European Olive, despite its current Mediterranean distribution.

The survival of the olive
Most of the olive trees in Israel are tens to hundreds of years old. It is assumed that the olive trees in the garden of the Gethsemane Church in Jerusalem were planted by the Crusaders, and that they are around 900 years old. Ancient olives in the Galilee are called by the local Arab population "Olives of Roman times", implying that they are even older. It is impossible to tell the age of the olive on the basis of its trunk rings, as one can in the case of other trees. The olive trunk rings are not created regularly at annual intervals, and the olive trunk assumes holes over the years, so that it is not a typical cylindrical trunk. One can evaluate the age of an olive tree only very generally, on the basis of the trunk diameter. After a hundred years or more, the olive trunk rots partially, and turns hollow or develops "windows", but even if the central trunk finally dies, it frequently manages to rejuvenate at the base, and theoretically the tree can live forever.

The blooming period of the olive tree occurs towards the end of spring, in the months of April and May. Then the tree is covered in many cream-colored, small flowers. Each flower has four sepals and four petals. The flowers disperse a good deal of pollen into the air, and they are pollinated both by the wind and insects (the pollen dispersed into the air is allergenic, and is considered a main cause for allergies in human beings). In the course of summer, the pollinated flowers develop into fruit – the olives. The fruit contains a single pit covered by pulp. The olive's pulp is especially oily. The percentage of oil in it can reach 30 percent or more. The green olive is in fact an unripe fruit, which is more watery, and consequently its oil content is relatively low. In autumn the green olives turn black spontaneously, and their oil content rises. Therefore, the green olive and black olive are not different varieties of the European Olive, but two different stages in the development of the fruit.

The olive leaves are rigid and live for several years. The leaf upper side is green and its bottom side silvery. This color characteristic is a marvelous adaptation of the tree to its habitat, and helps it contend with the region's difficult summer, and survive it. In summer the quantity of water available to the plant is limited. In addition, the olive has vulnerable points in the form of pores – special openings on the leaf surface, through which the plant exchanges gases with the environment (the exchange of gases is necessary for the process of photosynthesis and breathing), as a result of which it loses a large quantity of water. The pores on the olive leaves are located on the bottom side of the leave, and they are thus less exposed to sun radiation, and less water evaporates from them. In addition, the silvery color of the bottom leaf side is created by a dense felty layer, which covers the leaf, and constitutes an additional insulating layer, which further reduces loss of water from the pores.

The Olive in the service of man
The olive tree grows in Israel in vast quantities. In ancient times its products were exported to the Egyptian Empire. In that period man utilized olive oil to light lamps, which enabled continuous lighting in the dark hours, and freed man from camp fires (which required the gathering of wood and a good deal of maintenance). To the light of olive oil lamps, man could engage in cultural and administrative activities in the hours of darkness. Archeological finds show that olives were gathered by man in nature already in prehistoric times. In archeological findings one finds small olive pits, which resemble the wild olives. However, very rapidly man identified trees in nature with larger and tastier fruit. At first these olives were gathered for the purpose of producing oil and for eating. Later, man learnt to grow olives near his place of residence, and the olive turned into an agricultural crop, together with other important crops such as wheat, barley, lentils etc. These crops around the places of settlement enabled man to stop wandering in search of occasional food, and he toiled to propagate them.

At first olive propagation took place by means of sowing pits, but in this manner offspring that were variable genetically and variable qualities of olives were produced, which created a problem. Later on, man learnt to root young sprouting branches from the base of the olive's trunk – a-sexual (vegetative) propagation, and the offspring were identical in quality to the mother plant. In a new study by Dr. Oz Barazani from the Volcani Center, with German and Palestinian partners, it was discovered that man learnt to graft olives hundreds of years ago. They examined ancient olives in Israel and its environs, and found that the tree bases are different genetically, and the upper parts of the trees have a small genetic variation. These findings prove that sturdy and genetically varied domestic olives were used as culms, to which man grafted superior cultivated varieties that were not diverse genetically. In other words, man selected superior olive types, which he grew and propagated in an a-sexual manner, and distributed them in extensive areas. Today there are many superior varieties of the European Olive, which frequently look very different when compared to the wild olives.

The olive oil and the extract of olive leaves had and still have many uses in popular medicine as well. Oleic acid, which is produced from olive oil, is known as an efficient antioxidant, and therefore the consumption of olive oil is so healthy. Olive oil also served the soap and cosmetics industry. The anointment of the body with oil was reserved for members of the upper classes, and was used to remove dirt from the body. Another important use of olive oil was for ritual purposes.

Out of respect for the olive, the use of its wood in the alter was prohibited, and for the heating it was allowed to use only old trees, which no longer bore fruit. Already in ancient times the use of olive oil presses was extremely common in the country, and was used by the Canaanites, the Philistines and the Hebrews. The archeological finds show that for long periods there was a massive production of olive oil in the country, which was way beyond the local consumption needs, and, as mentioned above, the oil was exported to the Egyptian Empire, in which the desert climate prevented the massive cultivation of olives. 23 underground olive oil presses were found in the National Park of Beit Govrin-Maresha alone.

The Olive Harvest
The time of the olive harvest is one of the symbols of autumn. The exact timing depends on the various varieties, the area in which the tree grows, and whether the trees are irrigated or not. In Israel the harvest usually takes place in October-November, around Succoth, and various festivals are held around it.
Traditionally olives were grown throughout the country on mountainous terraces. In the past they were grown exclusively in the mountainous areas, together with almonds, figs, vines and pomegranates. In recent years olives are also grown in the Negev, where the trees are irrigated with saline groundwater, which is unsuitable for other crops. The success of olive cultivation in the Negev manifests itself also in the extraordinary quality of the oil, and the large yields. Today the largest olive groves are to be found in the Negev (they can be seen along the road in the Revivim area).

Yedidya Yerushalmi, a volunteer in the Jerusalem Botanical Garden, tells us about the Olive in the Bible and Throughout History

The Olive is one of the seven species with which the country has been blessed. The tree was common already in the period when the tribes of Israel settled in the country: "Thou shalt have olive-trees throughout all thy borders" (Deuteronomy:28:40). Olive oil was a vital and blessed component of the Jewish culture, and throughout the Mediterranean Basin. Inter alia it was used to anoint priests and kings, thus bestowing upon them sanctity and authority. The temple and its vessels were also anointed with oil: "And Moses took the anointing oil, and anointed the tabernacle and all tht was therein and sanctified them. And he sprinkled thereof upon the altar seven times, and anointed the altar and all its vessels, and the laver and its base to sanctify them." (Leviticus:8:10-11).

From the Jewish sources it transpires that eating olives began in later years. The commentary to the book of numbers 8, which is attributed to the Middle Ages states:"What is this olive: olives for eating, olives for drying, olives for oil, and its oil burns better than all the oils, and its leaves do not fall, neither in the sunny days nor in the rainy days". The impressive and unique sight of the olive tree, with its thick and winding trunk, its silvery leaves and pretty fruit, symbolized the Jewish People to the prophet Jeremiah: "The Lord called thy name a leafy olive-tree, fair with goodly fruit" (Jeremiah: 11:16), and under the inspiration of this phrase the Babylonian Talmud said "He who sees an olive in his dream, gains a good name for himself" (order of seeds, tractate of blessings, page 57). The olive also symbolizes a happy family life: "Thy wife shall be as a fruitful vine, in the innermost parts of thy house; Thy children like olive plants, round about thy table" (Psalms: 128:3). The use of olive oil for anointing the body was common also among the poor: "Wash thyself therefore, and anoint thee, and put thy raiment upon thee, and get thee down to the threshing-floor" (Ruth:3:3), while abstention thereof was one of the characteristics of mourning: "feign thyself to be a mourner, and put on mourning apparel, I pray three, and and anoint not thyself with oil" (Second Samuel: 14:2).

Banner Photo: Rachel Cobb