Impacts of spring freeze events on perennial tree fruit crops across the central and eastern USA

An extended period of warm anomalies during late winter or early spring, known as a false spring, can cause plants to exit dormancy prematurely, making them vulnerable to subsequent freeze events. This study investigates the impacts of springtime freeze events on a representative temperate perennial tree fruit crop across the central and eastern USA using a crop growth and yield model driven by daily meteorological data from 1981 to 2020. Results indicate significant regional and phenological variability in freeze damage frequency and severity. Damage was more frequent and severe in the Southern Great Plains, the upper Midwest, and the Appalachian Mountains, compared to the central and eastern Great Lakes, the Middle Mississippi Valley, and parts of the mid-Atlantic. Damage frequency generally decreased in later phenological stages, with the first two vegetative stages being most affected. A pattern of decreasing freeze events and false spring frequency, along with increasing bud fraction, was observed from south to north due to the interplay between spring warm-up timing, crop phenological development, and increasing seasonal vulnerability with decreasing sub-freezing temperature frequency and severity. However, sub-regional differences emerged, such as increasing freeze damage frequency in the Southern Great Plains and decreasing frequency in the lower Ohio Valley and Northern Great Plains. These regional differences, despite concurrent warming trends, highlight the complexity of overwintering crops' responses to environmental conditions and seasonal climatic cycles and the need for caution in estimating cold injury impacts on temperate perennial crops, particularly considering future climate change.