The olive tree (Olea europaea L.) is a fruit tree belonging to the olive family (Oleaceae), known as an evergreen, long-lived, and typical Mediterranean climate plant. This species, considered native to the Eastern Mediterranean, is a plant of agricultural importance widely cultivated worldwide, especially in the Mediterranean basin. Today, both the cultivated form (var. europaea) and the wild form (var. sylvestris) of Olea europaea exist in natural and semi-natural environments.
An Olive Tree Image - AA
Botanical Characteristics
The olive tree is typically a tree that can grow between 2 and 10 meters tall, exhibiting a twisted and often gnarled trunk structure. The leaves are oppositely arranged, lanceolate, leathery in texture, and typically covered with dark green on the upper surface and silvery peltate hairs on the lower surface. The flowers are hermaphroditic and occur in small clusters in the leaf axils. In terms of flower structure, it bears a 4-lobed calyx, a short-tubed corolla, and 2 epipetal stamens. Its fruits are fleshy drupes (stone fruits) and vary morphologically depending on the species and cultivar.
Cultivars
The three widely cultivated cultivars in Turkey are Ayvalık, Memecik, and Gemlik. The Ayvalık cultivar is particularly common in the Aegean Region and is preferred for olive oil production. Its average fruit size is 23.4 mm in length and 19.1 mm in width, and it is suitable for producing natural extra virgin olive oil in terms of oil quality. The Memecik cultivar is utilized for both oil and table olives and has a wider distribution; its average fruit length is 25.6 mm. The Gemlik cultivar is primarily used as black table olives in the Marmara Region; despite its high oil content, it requires refining for oil quality due to high acidity.
Anatomical Characteristics
A distinct organization of vascular tissue is observed in the transverse sections of the olive tree trunk. Beneath the epidermis, there is typically a 3-layered phelloderm, followed by sclerenchyma, parenchyma, phloem, cambium, and xylem. The xylem contains tracheae, tracheids, and abundant sclerenchymatous elements. The pith region is parenchymatous. In the leaves, the upper epidermis is covered with a thick cuticle, while the lower epidermis contains numerous stomata and peltate hairs. The mesophyll tissue consists of a 3-layered palisade parenchyma followed by spongy parenchyma. The veins show a collateral structure. No significant structural differences have been detected in the same cultivars grown in morphologically and anatomically different regions.
Form Pruning in Olive Trees (Döşemealtı District Directorate of Agriculture and Forestry)
Ecological and Agricultural Conditions
The development of the olive tree is closely related to the soil structure and content. According to soil analyses, Ayvalık soils in the Aegean Region are rich in organic matter and low in lime content, whereas Mediterranean region soils contain high levels of lime and are poorer in organic matter.
These differences indicate that the Ayvalık cultivar develops more successfully particularly in lime-free or low-lime soils. Marmara Region soils, on the other hand, have suitable organic matter content for the Ayvalık cultivar.
Economic and Health Significance
The oil obtained from olive fruit is rich in unsaturated fatty acids, primarily oleic (83%) and linoleic (15%). This content makes olive oil valuable for health. Olive oil has been traditionally used in medicine throughout history for its effects on the digestive system, bile secretion, and dermatological conditions. Due to antioxidants such as phenolic compounds and Vitamin E found especially in natural extra virgin olive oil, it has become a food extensively researched in modern science.
Distribution and Production
Olive farming in Turkey is most intensively carried out in the Aegean Region. The geographical distribution of Ayvalık and Memecik cultivars covers provinces such as İzmir, Aydın, and Manisa; while the Gemlik cultivar is particularly concentrated in Bursa and its surroundings. Turkey is one of the leading countries in global olive production, possessing approximately 72 million olive trees. Worldwide olive cultivation is largely endemic to the Mediterranean basin; 98% of the world's olive plantations are located in this region.
Findings for Cultivation
In olive farming, determining soil properties, selecting appropriate cultivars, and applying fertilization based on soil analysis are of great importance for productivity. High-lime soils, organic matter deficiency, and imbalanced nutrient elements can limit plant development. It is recommended to expand the areas where Ayvalık and Memecik cultivars can be efficiently grown, and particularly to graft wild olive trees in the Mediterranean Region to convert them into these cultivars.
