Olive trees are a species (Olea europaea) of genus Olea and family Oleaceae. It grows as a evergreen that mostly inhabits the Mediterranean area and California where the climate is warm and cool. It is best known for its fruit, which contains oil used in food, fuel, and so on. As most olive trees grow in the Mediterranean area, most olive oil is produced in this region.
The olive tree ranges from 8 to 15 meters high, and the leaves are about 4 to 10 centimeters long. The leaves fall in about two years and regrow in the spring. The olive tree has a flower, which is small and white, and hidden in the leaves. The olive tree makes two sorts of flowers: perfect flowers which have male and female of reproduction, and staminate flower, as the name says, it has only stamens. Moreover, the olive tree produce fruit which has a purple color of plumps and oval shaped. The olive tree takes about 4 years to bear the plump.
In these days, we use olive in our living, such as olive oil used in food and olive leaves used in the medical or drink. In the ancient, people made a tea for the cough, fevers and the normal illness by the olive leaves. 
There are two reproduction of olives: self pollination and cultivation. First, pollination can be the first and important steps to set the fruit or crop. Success in pollination is how fast the pollen grow in the embryo sac. There are two environmental conditions that can set the fruit's level are stressing environmental conditions and no stressing environmental conditions. The olive should get a nitrogen to fertilizing well. The olive trees in Mediterranean, fertilized in every each years.  There are three cultivations that the growing olives should have: Climatic requirements, soil requirements, and water and irrigation. First, the olive trees are normally grow in 30 to 45 degree. Mediterranean has the best climate to grow the olive because they have hot in summers and cool in winters. The temperatures below -5 degree can damage the fruit and temperature below -10 degree can kill the tree. Second, the olive tree can adapt to the soil with 8 potential of hydrogen. And they need about 1 meter deep to root can set down. In addition, the olive tree have to produce the well nutritioned fruits and the better taste fruit and it all depends on the soil's conditions. Third, the olives use water in the growing season because water can effect directly to growing. There are two seasons that the water is extremely needed: growth to flowering and growth of oil quantity.
The olive trees are native plants in the Mediterranean where the climate is warm and cool and they are now cultivated all over the world. For example, Olea Europaea (the subspecies: Europaea) is cultvated in Hawaii and island of Maui. The olive trees are extended in the west of eamuku camp which is about 900 meters high and also at the Parker Ranch. And then, at the island of Maui, olive trees are extended at the Kula region where is 830 meters high of the grassland.  And also, the Olea Europaea (subspecies: Africana) are mainly cultivated in the southern Africa and they are habitated near by water, such as the stream or river, also at the mountains. The olea Europaea (Africana) is existing by the cultivators who took the experiment to form the olive tree in Mediterranean region included southern Africa, Australia and other countries with Mediterranean climate. 
History of Olive Oil
In the ancient of Greece, the olive oil was rare as gold, it was also used in medicinal, and people can use or show it to make a boast people about the power and wealth. Crete, in Greece, was the first place to cultivate the olive tree, and it started in 3500 BC and after 2000 BC the olive oil was the largest economic item in Crete. Moreover, they export them world widely and then the olive oil became a nutritious food in the Greek in that period. Jewish people used the olive oil in their spiritual way, and they only used the olive oil as a fuel. And also, in their religion, the olive oil was the symbol of strength and many other religion use the olive oil as the God's important or unique work. For example, in the Orthodox Christians were using olive oil for blessing and moreover, they are still using olive oil as a fuel for the lamps. Today, we are using olive oil in the food, medicines, fuel, and even if in the soap, and cosmetics. 
Pests and Diseases
List of pests and diseases from olive trees.
- Black Scale
- Olive lace bug
- Olive knot
- Peacock Spot
- Olive Moth
- Verticillium Wilt
- Olive Shoot Moth
- Olive Scale
- Circulio Betle
- Olive classification multiple author. Encyclopedia (wikipedia)
- Growing of Olive Modern Olives.
- Taxanomy USDA PLANTS
- Olea Europaea Multiple Authors. California Rare Fruit Growers.
- Distribution of Olea Europaea Forest Sarr, Kim Strr, and Lloyd Loope United States Geological Survey
- Ecology of Olea Europaea Multiple Authors. World Agroforestry Centre.
- Disease from Olive Tree Unknown Author. Olive Business