Stock Photo: OLIVE TREE. OLIVE TREE Photo essay. Olive tree near St Michel le Frigolet Abbey in Tarascon France. Olive farming. The Barres mill, built in 1992 on the site of the old mill, uses modern technology to press the olives. Once the olives are washed and crushed, a mixer-press extracts 70% of the oil contained in the olive paste. The liquid is sent through a centrifuge which separates the oil from the water. The olive paste containing the remaining 30% of oil is mixed with the extracted water