Olive Tree Notes

Olive trees attain significant size but have a slow growth rate.
Average height: $15-20$ meters.
Under agricultural practices with pruning, the height is generally $4-5$ meters.
Fruit: Drupe, botanically similar to apricot or peach.
Different olive colors indicate the maturity of the fruit.
Physical characteristic: Spindle-shaped trunk.

Cultivated variant of the wild olive, known as "oleaster."
Scientific classification: Olea europaea subsp. Europaea var. sylvestris (Green, 2002).
Belongs to the Oleaceae family, genus Olea.
"European Olive" is derived from Latin.
Olea europaea is grouped as a complex with six subspecies (Marone and Fiorino, 2012).

Wild olives are shrubs, while the cultivated variety is a tree.
Significant genetic differentiation exists between cultivated and wild populations, despite feral and admixed forms (Besnard et al., 2018).
Cultivar: Complex patchy pattern.
Insular and mainland olive domestication have undergone different selection processes (Besnard et al., 2001b).
Both varieties are diploid and allogamous (Green, 2002).
Difficult to narrow down the origin of cultivar genetically.
Suggestions: Allochthonous origin, multilocal selection of cultivars.

Adapted to grow in diverse climates, with variable altitudes and soils (Fanelli et al., 2022).
Olea complex distribution spans Southwest Africa, parts of the Arabian Peninsula, the Mediterranean into Mesopotamia, and the Canary Islands.
Olive groves in the southern Levant are mainly constructed on the coast, inland, and mountainous areas of the southern Mediterranean; cultivation zone toward arid and semi-arid zones of the Mediterranean (Barazani et al., 2023).
Main ecological characteristics to distinguish between wild and cultivated variants (Besnard et al., 2018):
- Oleaster occurs in scrublands, restricted to remote areas of the Mediterranean basin.

First uses (Besnard et al., 2018):
- Emerged in the Middle East in the Levant during the Neolithic period.
- Involved in olive oil trade during the Chalcolithic period; domestication occurs afterward.
Human-mediated spread (Besnard et al., 2018).
Palynological and archaeological evidence constructs a history of agriculture, from the earliest use of olive oil extraction to local farming communities.
Introduced into Greece, Egypt, and western Türkiye (Vossen, 2007).

Major producers: Spain, Italy, Greece.
Ancient Greece: Minoa and Mycenaean trade between Egypt (New Kingdom) during the late Bronze Age.
Oldest olive trees reside in Crete.
Greek mythology: The creation of Athens.

Use by Indigenous people.
Agriculture is defined by grafting wild olive trees and is an important priority of conservation (UNESCO - Traditional Knowledge, Methods and Practices Concerning Olive Cultivation, 2022).

One of the oldest olive trees resides in groves in Southern Lebanon.
Economy is heavily reliant on this agricultural product in the West Bank in the State of Palestine.

The tree is an important historical, cultural, and agricultural symbol across many Mediterranean communities.
Climate change and emerging diseases affect cultivated olives.
The Mediterranean region is described as a climate change “hot spot” with predicted shifts in precipitation and a rise in temperatures (Martins, 2024).
Researchers reported that a key area of Spanish olive oil production in Catalonia may become unviable within 20 years due to these increasing temperatures and water shortages (Ozdemir, 2016).
Solutions for sustainable agricultural practices (Martins, 2024):
- Adaptation strategies: cover cropping, mulching, soil amendments, optimized irrigation systems, pruning.