Olea europaea var. Europea is the main cultivated species belonging to the family, Oleaceae, which includes 30 genera and 600 species (1). Olive trees are very abundant in high monounsaturated fatty acids and other active minor components such as tocopherols, sterols and squalene (8). Interestingly, there has been a reported occurrence in the different levels of high variability in oil concentration of these trees. This therefore implies a deep importance of certain genotypes for maximum growth and best breeding of olive trees.
Olive tree leaves are arranged opposite of each other, in a lanceolate shape (tapering to a point at the apex and at the base) and they are about 8 cm in length (2). The color of the leaf is white on the underside during the winter and colder seasons. On the upper side, the leaves are bright green during the warmer seasons. The olive tree flowers, also known as burrs, are usually very small and clustered. They are characterized by four white petals and a strong fragrance. Olives are ovoidal, meaning there is only one stone inside. The pits inside olives can range from 1.5 to 3 cm. They start off as green and as they mature, they turn black. Olive trees are expected to live about 300 to 600 years, however, there are some that can live for up to 1000 years (4).
The olive tree is native to Asia Minor and spreads across Iran, Syria and Palestine, stretching over the Mediterranean basin for over 6,000 years (4). During their growing seasons, best results will be in late spring as they usually flourish around May. During the summer and fall seasons, the green pigment in olives then turns black. Olive trees thrive in full sun and hot/dry environments. Usually by early autumn, olives are fully grown. However, it isn’t until late November and early December that olives can be harvested for products such as olive oil, usually in mountainous areas (7). Olive trees are usually frost hardy once they are established in any environment, but are more susceptible to frosting when younger (9). They can even tolerate temperatures as low as 14 degrees Fahrenheit. However, it isn’t ideal for olive trees to grow in these low temperatures for long periods of time. In some areas, olive trees can harvest in September, but it isn’t as common as November/December.
Olive trees do not thrive indoors. However, if olive trees are planted indoors, it is recommended that they are best suited near bright windows, with at least 8 hours of direct sunlight. Even in pots, olive trees do best in the ground outdoors. They also need moist soil to grow adequately, but not wet soil. Water is essential to bear fruit on olive trees and allows for fruit not to dry out, like many other plants.
Olive trees can survive many years in a pot, however, it is best for them to be planted in the ground. Those planted in pots need to be watered more often than their counterparts (6). Olive trees are very susceptible to many types of insects, including scale, so keeping an eye on them is key. Additionally, periodically spraying water on these trees can be helpful, especially in dry, heated, winter homes (6). When watering olive trees, lots of watering is recommended during the hotter seasons, but when fall and winter roll around, less water is best. However, with less water, it is important to not let the soil dry out completely (9). When utilizing fertilizer for olive trees, use one that is rich in nitrogen and other nutrients. With these additional nutrients, they will supplement otherwise missing minerals for adequate and maximum growth (9).
The environmental impact of olive trees depends a lot on the size of fields used and the methods used to harvest them. Small olive farms have less of an environmental impact than larger, industrialized farms. Many farms utilize a lot of land, which in return, leads to soil erosion (15). Soil erosion causes less fertile soil which can also lead to desertification. Soil erosion can arise from the type of soil in the area, the amount of rainfall, the slope and how farmers are treating the land. Currently, many olive tree farms only house olive trees with no other smaller plants, leaving many olive trees vulnerable to diseases and other predators.
Culinary Uses
The olive tree gives life to different types of food such as olive oil and olives. About 90% of olives are turned into olive oil and 10% are used as table olives. Olive oil comes directly from olives, which are the fruit of olive trees. Olive oil is consumed in different parts of the world and has different designated terms based on its location. Olive oil can be described as having a range of colors from greenish-brown to light yellow, depending on growing conditions and how ripe the olives were when the olive oil was made. Olives are what grow directly on these trees and can show up either green or black. Both types of olives can grow on the same trees, but black olives indicate ripeness and green olives don’t. The olives that are grown and sold commercially usually aren’t fresh and are sold in cans because fresh olives are described as very bitter (5). In order to be consumed, olives undergo a process to become debittered which starts by putting them in a lye solution, which will naturally take out the bitterness. Then after being soaked in the solution, a series of cold-water rinses will get rid of the solution (5). Most commonly, olives are snack foods that pair with many different types of food. They are used in different types of food all over the world. For example, in Italy and Provence, olives are baked into breads, dips and pastes. In Spain, they appear in some pasta sauces. They are also famously used in many Greek and French salads (5).
Medicinal Uses
Olive oil has many health benefits and can be used all over the body. Olive oil can be used to make creams and ointments. It restores the moisture levels of the skin due to the large amount of fatty acids present and can reconstruct skin cell membranes because of the presence of oleic acid (14). Additionally, people use the oil from the fruit, seeds and leaves to make medicine. Even though olives aren’t directly ingested to combat specific diseases and/or conditions, olive oil can be incorporated into daily living to help with heart disease, high cholesterol and high blood pressure (12).
Significance to Cultural Communities
Olive trees hold a lot of significance in many cultures and religions, with great importance in Islam and Christianity, to name a few. The Prophet of Islam, Muhammad, advised his followers to apply olive oil, which can be harvested by olive trees, to their bodies (4). Additionally, olive trees are referenced in an oath coming directly from Allah, God in Islam, which demonstrates the sacred nature of the olive (3). In Christianity, God’s followers are frequently compared to olive trees and are seen as beautiful, according to the Old Testament in the Bible (10). The New Testament of the Bible also uses olive trees to illustrate God’s salvation to his followers. Similar to olive trees, branches or people that followed Jesus would bear fruit, just like olive trees that would receive enough nutrients to cultivate olives. It is used in many religious ceremonies, such as during baptisms in Christian churches, similar to holy water.
Culturally, olive trees are very closely connected to Greek culture as they have such significant cultural, social and economic sustenance to the Greeks. For many generations, olive trees served as a symbol of hope, peace and victory. For example, when a child is born in Greece, an olive tree is planted, representing prosperity, luck and good fortune (13). Over time, both the olive tree and child will grow together, growing more olives and surviving decades with the family. Even in Greek mythology, Athena, the goddess of wisdom, art and peace, brought the first olive tree to Athens, teaching people to cultivate it for its fruit and oil.
First/Community Voice
“Growing up in a Middle Eastern family, anytime friends or family gather, there’s always two staples that are always presented and that’s chai and olives. Olives are deeply rooted into Middle Eastern culture, and sharing them with a friend or family member shows a sign of the love and friendship that one harbors for the other. Not only this, but the influence of olives in the Middle East runs deeper than being a sign of friendship and it's even used to classify wealth and status. In the Palestinian town my dad is from, his family is considered the “main” family due to their wealth that’s derived from having a large olive tree farm in the neighboring valleys. As the main family, they inherit mayoral duties and hold the responsibility of the town. With that being said, olive trees’ significance in Middle Eastern culture can be interpreted in many ways in accordance with one’s connection with them.
Personally, I view olives with great fondness, and I find that it makes any meal better when it’s served along with it. I was born and raised in America but upon finally visiting my dad’s olive tree farm, I still felt a great sense of pride towards it. This is because I understood the importance of it and knew that all the olives and olive oil my family, and extended family, eats came from the trees I was seeing, and it filled my heart with warmth to know these trees were providing a sense of community to everyone. Whether it’s owning an olive tree farm or simply sharing olives with a good friend, the role olives hold in Middle Eastern culture is one that represents peace and amity.”
Story from Melaq Abdeljaba, collected by Grace Fick in the summer of 2020
__________________________
1. Chiappetta, Adriana, and Innocenzo Muzzalupo. “Botanical Description.” IntechOpen. IntechOpen, December 5, 2012. https://www.intechopen.com/books/olive-germplasm-the-olive-cultivation-table-olive-and-olive-oil-industry-in-italy/botanical-description.
2. “Characteristics of Olive Trees.” Characteristics of the olive tree. Sabor Artesano. Accessed September 8, 2020. https://www.sabor-artesano.com/gb/olive-tree-characteristics.htm.
3. Echolls, Taylor. “What Do Olives Represent in Islam?” Synonym, September 28, 2017. https://classroom.synonym.com/what-do-olives-represent-in-islam-12087654.html.
4. “History of the Olive.” History of the Olive | The Olive Oil Source. Accessed September 8, 2020. https://www.oliveoilsource.com/page/history-olive.
5. Hopley, Claire. “Cooking with Olives, the Mediterranean's Finest Fruit.” Daily Hampshire Gazette. Concord Monitor, April 15, 2016. https://www.gazettenet.com/Life/Food/Cooking-with-olives-the-Mediterranean-s-finest-fruit-1461451.
6. “Know about Planting Olive Trees in a Pot.” McEvoy Ranch, 2020. https://www.mcevoyranch.com/pages/planting-olive-trees-in-a-pot.
7. Masterman, E.W.G. “Olive Tree in the International Standard Bible Encyclopedia.” International Standard Bible Encyclopedia Online, 2020. https://www.internationalstandardbible.com/O/olive-tree.html.
8. Navas-López, Jose F., Juan Cano, Raúl De La Rosa, Leonardo Velasco, and Lorenzo León. “Genotype by Environment Interaction for Oil Quality Components in Olive Tree.” European Journal of Agronomy119 (June 23, 2020): 126115. https://doi.org/10.1016/j.eja.2020.126115.
9. “Olive Tree - Easy Growing and Care Guide.” Green and Vibrant, November 13, 2019. https://www.greenandvibrant.com/olive-tree-care.
10. “Olive Tree Imagery.” That the World May Know. Accessed September 9, 2020. https://www.thattheworldmayknow.com/olive-tree-imagery.
11. “Olive Tree.” NETBible: Olive Tree. Accessed September 9, 2020. http://classic.net.bible.org/dictionary.php?word=OLIVE TREE.
12. “Olive: Uses, Side Effects, Interactions, Dosage, and Warning.” WebMD. WebMD. Accessed September 9, 2020. https://www.webmd.com/vitamins/ai/ingredientmono-233/olive.
13. “The History of the Olive Tree.” Abea, 2015. https://www.abea.gr/en/history-of-olive-in-crete/.
14. “The Olive Essence : Products.” Esencia de Olivo, 2020. http://www.esenciadeolivo.es/en/the-culture-of-the-olive-tree/products/.
15. “Why Olive Oil Is Bad for the Environment.” The Green Vegans, April 29, 2018. http://thegreenvegans.com/why-olive-oil-is-bad-for-the-environment/