The olive tree and its phenological states
The development cycle of the olive tree, like any other plant, is ruled by the seasons. After remaining asleep during the winter, in spring this tree shows its splendor and begins to wake up from its lethargy. Then it starts its journey through the phenological stages, which will culminate in autumn with the arrival of the fruits.
The olive tree, like any plant, organises its life cycle in different phases. Throughout the year, this eminently mediterranean crop plays a leading role in various phenological stages that begin in spring and last until the summer and autumn months.
Sprouting: the olive tree awakens from its winter slumber
The arrival of spring causes an increase in temperatures and hours of light. This is the start of one of the moments most awaited by olive growers: the sprouting. A magical period in which after a long winter, the armpits of the leaves of the olive tree show their first buds.
Olive trees start to sprout in spring
Some of these known as flower buds will eventually give rise to flowers – also called rapes – from which, later, the fruits will sprout. Others, will follow their way, becoming first shoots and then branches which, in turn, will generate new buds, guaranteeing a new cycle. These are the so-called vegetative buds.
Visually, the two buds present imperceptible differences when they remain closed and in a protected place on the tree, precisely where the leaf adheres to its branch, but their future will depend on the biochemical mechanisms that take place before the arrival of winter.
Budding changes the appearance of these trees as the sap reaches their leaves pushed by the roots. This is a sign that darkens or lightens their canopy as a prelude to their next stage: flowering.
The flowering, in May
Generally, the flowering of the olive tree takes place in the middle of May, however, the region where the tree is located, the variety or the climate can vary the date. At the moment, an increase in temperatures brings forward this moment in which the olive tree is covered with flowers waiting to be fertilized. This is precisely what has happened this year in Jaén, where the high temperatures of April have led to a preview of this visual spectacle.
During approximately one week, this plant of sexual reproduction shows a great amount of bunches of flowers that wait to be fertilized becoming thus new fruits.
Some of these whitish-petal flowers are hermaphrodites, being able to generate a new fruit. Others, however, only produce pollen and are identified with the male sex.
In any case, this idyllic period does not last more than one week, although from the time the first flower opens until the last flower opens, approximately three weeks may pass.
At the end, very few flowers will be fertilized (about 1-2%) and become fruits. However, this figure will bring a good harvest in each season.
The flowering has come to an end and the fertilized flowers are coming off the petals! The process of fruit formation, known as fruit set, begins.
During this moment, which corresponds to the arrival of the summer, the olive tree shows in its glass the future harvest that it will have to feed during the next months, but it also takes advantage of it to carry out a natural selection of its fruits letting fall those that it will not be able to feed. These will be approximately 50% of your olives and will allow you to guarantee future reproduction and survival.
The fruit setting coincides with the arrival of summer
In June, when the temperatures are warmer and the hours of light are longer, the drupe, that is, the olive, begins to form. During this month and before the stone (endocarp) begins to harden in July, the olive will experience a cellular multiplication that will decide its final size.
With their green skin (pericarp), the olives will continue to grow bigger during the summer and transform the reserves they have accumulated in their pulp into oil. This process is called lipogenesis.
The first stage of the fruit’s evolution will finish when the stone is completely hard, leaving behind its gelatinous appearance.
The summer begins to weaken and the fruits of the olive tree face a crucial stage, which becomes evident when they defy veraison or, in other words, when their green colour loses intensity, darkens and begins to turn towards yellowish or pinkish tones that, after passing through the garnets, will lead to black.
In October, the olive trees are ready to be harvested
The beginning of this chromatic evolution presages the imminent harvesting of the olives. Some are greener and others more mature, but all of them are prepared to provide all their juice.
This is the culmination of a long and intense process in which the olive trees are dressed in their best clothes to welcome the harvest of their fruits!
In the following posts we will explain how the olive harvest is done and how all its juice is obtained from it.