By: Sofía Cáceres – Technical Manager at Tierraverde
Frosts represent a silent threat that can destroy what took months to develop in minutes. In cherry orchards, these extreme weather events cause catastrophic losses ranging from 26.7% to 99.3% of production, depending on the species and environmental conditions.
The 2024 season left a profound mark on the central producing areas of Chile. Temperatures dropped as low as -3°C in regions such as Valparaíso, O’Higgins, and Maule, causing significant losses in orchards without protection systems. The economic impact resonated in every affected producer, transforming harvest hopes into multimillion-dollar losses.
When Ice Attacks Cells
Damage from frost begins at a microscopic level. Ice crystals form within plant tissue following two lethal pathways. Intracellular freezing generates crystals directly in the cell protoplasm. Extracellular freezing forms ice between the cells, creating an osmotic deficit that dehydrates and collapses vital structures.
Speed determines the difference between life and death at the cellular level.
When cooling occurs rapidly, the damage becomes irreversible. The ice invades both the intercellular spaces and the interior of the cells simultaneously, preventing any adaptation. Cell membranes break down. The protoplasm disintegrates. The affected tissues turn a characteristic dark color that announces death.
Critical thresholds are clearly defined. At -2.22°C, 10% of the buds are lost. At -4.44°C, the devastation reaches 90%. Each degree below freezing point exponentially multiplies the damage.
Vulnerability According to Phenological Stage
The susceptibility of the cherry depends dramatically on its developmental stage. From swollen bud to exposed cluster, vulnerability reaches its maximum. It’s as if nature particularly punishes this early spring awakening.
Studies from the Southwest Michigan Research and Extension Center revealed alarming patterns. Crops in the tightly clustered stage suffered damage from 51.9% to 76.9%. Those in the green tip stage suffered losses from 50% to 62.6%.
Duration Intensifies Impact
Prolonged frosts cause greater destruction than brief temperature drops. During winter, these episodes can last for hours, especially at dawn. Every additional minute of exposure to cold reduces recovery chances.
Flowers Lost, Crops Ruined
Within each cherry flower, the pistil is the most vulnerable reproductive organ to cold. This female reproductive structure succumbs first, followed by the stamens and finally the petals. The death of the pistil condemns the flower irreversibly.
The diagnosis is simple but clear. Cutting into a swollen bud, a black pistil reveals death. A green pistil promises life. For cherry trees, each flower counts. Unlike apple or pear trees, which can lose 50% of their flowers without seriously compromising the harvest, cherries require multiple fruits to reach commercial yields.
When Damage Persists Until Harvest
Frost leaves invisible scars that manifest months later. Stressed trees produce fruits with compromised cellular integrity, lower firmness, and a shorter shelf life. The sugar accumulation patterns are altered. The acidity profiles become unbalanced.
bound calcium decreases significantly in frost-affected fruits. This critical indicator predicts future problems: higher susceptibility to pitting, accelerated dehydration of the peduncle, and increased vulnerability to fungal infections during storage.
Commercial Implications Are Dire
Export markets, especially China, demand higher quality standards. Fruits from stressed trees rarely meet these requirements and are sold in local markets at significantly lower prices.
Mass Fruit Drop: Protecting Future Generations
Fruit drop due to frost is a complex physiological response to stress. During the first 25 days after full bloom, any fruit that surpasses this period will have successfully completed the initial setting.
Frosts disturb this delicate balance. Damaged tissues require extra energy to repair, leading to competition for limited carbohydrates. The tree, in its evolutionary wisdom, sacrifices fruits to ensure its survival.
Death of Young Trees and Long-term Losses
Young cherry trees, especially those between 1 and 5 years old, face particular risks. Winter cold damage in these trees follows characteristic patterns, mainly affecting the xylem rather than the phloem, which is typically damaged.
Damaged wood takes on a light brown color. The damage lines match exactly the snow depth during the cold event. It is a precise snapshot of the disaster etched into the tree’s anatomy.
The mechanism is treacherous. Warmer winter periods raise the trunk’s temperature, especially when reflected sunlight from snow increases the temperature of the bark. Sudden cold spells catch the tree unprepared, unable to re-acclimate. Total death can occur.
New Challenges of Climate Change
Climate change is redefining risk maps for cherry production. The transition from El Niño to La Niña in 2024 brought lower precipitation and episodes of cold temperatures during the critical flowering period.
The paradox feels strange.
While average temperatures are rising, climate volatility intensifies the risk of devastating frosts. The warmer periods accelerate the development of flower buds, making them more vulnerable when cold waves inevitably arrive.
Growers face an unpredictable enemy. Traditional strategies based on historical data are losing their effectiveness against increasingly erratic climate patterns. As a result, there is an urgent need for more robust and adaptable protection systems.
Frosts will continue to be a structural threat to cherry production. Each spring brings the anxiety of clear nights and falling temperatures. The battle between cold and life repeats itself, with winners and losers, in a game where stakes are high and the rules change constantly.
