The wild olive tree is found in the entire Mediterranean basin. Broadly speaking, the Mediterranean climate is defined by its hot, dry summers with relatively rainy and mild fall and spring, yet there is always great variability and uncertainty both within the year and from year to year.
In this climate, olive tree cultivation was developed, and later it expanded in dry-farming to colder areas tolerated by the wild olive trees, be it to the north, or gradually up from sea level to higher altitudes. The olive tree is genetically designed for the Mediterranean climate, and this cannot be modified.
The olive tree is adapted to carry out its most intense physiological efforts at the most favorable times, which are spring and fall.
During these moments of high metabolic activity, the olive tree is more sensitive to water stress, which greatly impacts the harvest and even the harvest of the following year.
On the other hand, in winter, the olive tree is in a relatively dormant state, whose intensity depends on the temperature. So, even in winter, with mild temperatures and sufficient humidity in the soil, the olive tree is able to be photosynthetically active, and can even continue to grow when there are few olives on the tree.
At the other extreme, the Mediterranean summer is characterized by very high temperatures and practically no precipitation. Transpiration is very high, and the water content of the soil is low and and declines even more throughout the season.
During this time the olive tree starts up its physiological ammunition to protect itself as much as possible from cellular oxidation and reduce transpiration. It synthesizes large quantities of cellular antioxidants (polyphenols), and reduces transpiration by partially rolling up its leaves to insulate the stomata, located on the underside.
In summer, plant growth and fruit growth practically stop, depending on the severity of the summer and the varietal. Summer is a time for giving the olive tree some physiological rest, comparable to the pause in winter.