Strategies for managing spring frost risks in orchards: effectiveness and conditionality—a systematic review

Drepper, B., Bamps, B., Gobin, A. et al. Strategies for managing spring frost risks in orchards: effectiveness and conditionality—a systematic review. Environ Evid 11, 29 (2022). https://doi.org/10.1186/s13750-022-00281-z

In temperate fruit orchards, spring frosts are among the most important causes of yield reduction [1]. During the winter months, trees are in a dormant stage, without vegetative growth and with high tolerance against low ambient temperatures [2]. During the spring months, and throughout the plant development stages, the reproductive organs situated in the flowers are sensitive to temperatures below defined frost thresholds [3]. A single frost night on 19^th April 2017 led to 24% less apple and 12% less pear production in Europe [4] and frost in 2021 lead to damages of 24–30% in French vineyards [5].

In the context of a warming climate, there is agreement that in western and eastern Europe, Australia and South Africa flowering of pome, stone and vine fruit starts earlier [6,7,8,9,10]. However, also the last day of frost in spring occurs earlier [11,12,13,14], resulting in regional studies with contrasting conclusions about the evolution of frost hazard during flowering. Over the past decades, frequency and severity of frosts after bud break decrease in the United States and increase in Europe and Asia [15]. For smaller regions, disagreement persists in the literature, due to heterogeneity in the applied phenological models, climate models and assessment methodologies [11]. The resulting hypothesis is that despite the warming climate there is no evidence that frost will be of no concern in the future and preventing frost damage is expected to remain a major challenge for fruit producers.