Wind is always a weather factor that should not be underestimated in agriculture, as it is capable of damaging all plantations, from trees, shrubs and even covered crops. If the species is fragile or if there are delicate parts, flowers and fruits, the violent movement of the air can cause breakages and injuries due to the rubbing of the leaves and the branches themselves.
Olive grove wind barrier, 6 years after planting. The wall completely protects the trees (lemon grove) because it is higher than the canopy structure.
Windbreaks are effective in protecting orchards from strong and cold gusts. In this regard, agronomist Vito Vitelli explains: "Gusts become dangerous when they exceed 50-60 km/h, and then they become devastating for plants and structures when they exceed 90-100 km/h. But the goal should not be to completely isolate the field from air movement, which is very important to prevent moisture stagnation, for example, or to facilitate the circulation of pollen or the movement of pollinating insects. We need a semipermeable barrier that can be made either with plants or vertical mesh.
Almond grove protected by olive trees
Plant windbreaks are preferable because, in addition to the wind speed reduction effect, they have a real filter function. Areas protected by vegetation are cooler in summer and warmer in winter. In addition to the air conditioning effect, these barriers, which have a positive impact on the landscape and biodiversity, filter the air from salt and particles with a phytotoxic and abrasive effect carried by the wind. Strong winds not only directly damage plants, but also protective structures, causing disasters and major economic problems.
Kiwi plant after a storm
How they work and for which crops
The most common species used as wind barriers in Mediterranean climates are olive trees, reeds (Arundo spp), cypresses and eucalyptus trees. According to the agronomist, it is necessary to build a wall 6-7 meters high, which should be built around the perimeter of the plantation. However, the effectiveness of the barrier is not unlimited. It should be repeated every 80-100 meters, always perpendicular to the wind.
Windbreak made of reeds
"Windbreaks are recommended for the protection of all crops exposed to wind, both under normal conditions and in the case of devastating exceptional events, the latter of which are becoming more frequent due to climate change. They are unavoidable in the case of valuable crops with very high income, in high-density crops (lemon and kiwi orchards) or super-intensive crops (such as pear or apple orchards), where there is a high economic investment in terms of trees and equipment."
What is the preferred barrier for farmers?
In the last few years, there has been an increase in the use of single-stem olive trees, because they are a widespread species in Italy, fast growing, provided that the irrigation and the canopy are properly managed, with a dual purpose, combining the protective function with the productive one.
Pear orchard a few months after transplanting and protected by olive trees (Sicily)
"The olive tree is well suited as a windbreak because it is a species that is easy to manage and non-invasive to the crops it protects," continues Vitelli. "The plants are placed along the row at 1.80-2.20 meters and raised in a single axis with the help, for the first three years, of braces and support structures. Not very long (maximum 1.00-1.30 m), strong and very flexible branches branch out from the solid central axis, mainly in the direction of the wind. The branches are gently exposed to the moving air, favoring its movement and reducing its force.
The proximity of the plants along the row creates a relationship between the root systems, generating a moderation of branching development, self-regulation of vegetative balance and early entry into production. In the wall, the approximate arrangement of the plants allows an easy management of the pruning, which is carried out manually every year, acting mainly on the lower branches and consisting of a few cuts."