Strong winds – how to tame the beast

Tree productivity is directly correlated to tree volume. Therefore, wind-affected orchards might experience delays of a year or more before coming into production. This delay can have economic consequences. Without a commercially viable crop, setting a crop in the early years becomes unjustifiable.

Strong winds and your citrus orchard

When establishing new citrus orchards, it is important for trees to develop optimal canopy volume, including good shoot internode length and fully developed leaves. In areas with frequent high winds, it is vital to have a proper windbreaking system to protect the young trees. Failing to do so will cause a delay in the return on investment because of reduced tree growth rate and canopy size, bark damage at ground level, bent or fallen trees, few or no fruit on the windward side, lesions on the leaves and stems and limb breakage.

Case Studies

Jannie Toerien, Technical Director at Patrysberg, has observed similar delays in production due to strong winds. In an orchard of soft citrus planted in 2017 on a windy slope, they erected a net structure over most of the orchard but left a small section uncovered. The trees under the 20% white net structure began production in 2020, while the uncovered trees are only expected to produce during the 2021/2022 season.

Further evidence of wind protection benefits comes from a recent orchard visit in Citrusdal, where young Midknight Valencias planted in December 2021 showed clear advantages in canopy volume in areas sheltered by a dam wall. Trees in sheltered areas had longer internodes, fully expanded leaves, and greater height and volume compared to those in wind-exposed areas. These trees are likely to come into production earlier, emphasizing the benefits of wind protection.

A Midknight Valencia tree exposed to strong frequent winds. Plant date: Dec 2021
A Midknight Valencia tree in the same orchard sheltered from the predominant wind behind a dam wall. Plant date: Dec 2021.

The Role of Windbreaks and Net Structures

A study conducted in a 23-year-old Valencia orchard in New South Wales, Australia, by Freeman in 1976, revealed that installing 5.2-meter artificial windbreaks resulted in a mean increase of 8-12% in canopy volume compared to areas without windbreaks. This significant finding suggests that if windbreaks can enhance canopy volume in an established orchard—where trees partially shield each other—the benefit for a newly established orchard would be even more substantial.

A protected tree canopy volume can be at least 20% larger than that of unprotected trees exposed to constant high winds. Properly installed shade net structures can reduce wind speeds by up to 90% in areas with frequent strong winds, thereby significantly mitigating wind damage.

When asked about minimizing wind damage through fertilization and irrigation, Rabe responded, “The best fertilization practices cannot compensate for wind damage. Water and fertilizer are optimally utilized by healthy, fully expanded leaves. Damaged and curled leaves cannot function properly and cannot utilize applied nutrients optimally.”

Some solutions

Growers in wind-prone areas are encouraged to invest in high-quality natural or artificial windbreaks or complete net structures before planting. This investment can minimize risks, reduce damage, and prevent delays in reaching production. Protecting young citrus trees from strong, frequent winds not only promotes healthier growth but also ensures that orchards reach commercial viability sooner, maximizing long-term profitability.

By prioritizing wind protection strategies, growers can safeguard their young citrus trees against the adverse effects of strong winds, ultimately enhancing tree health, accelerating growth, and ensuring earlier and more productive harvests.

For more information and solutions, read the full article in ROOTED magazine #1.