Impacts of spring freeze events on a perennial tree fruit crop across the central and eastern USA.

Abstract

This study uses a crop simulation model driven by 40 years (1981-2020) of daily gridded meteorological data from PRISM to assess the impacts of spring freeze events on cherry trees, a representative temperate perennial tree-fruit crop, across six regions of the central and eastern USA: the Northern and Southern Great Plains (NGP, SGP), Upper Midwest (UMW), Ohio Valley (OHV), New York-Pennsylvania (NY-PA), and Virginia-North Carolina (VA-NC). Freeze damage exhibits a clear latitudinal gradient, with damage frequency and severity decreasing from south to north. The most frequent and severe damage occurs in the SGP, followed by VA-NC, while the least is observed in the UMW and NY-PA. Damage frequency decreases as phenological stage advances, with the first two vegetative stages being the most affected. False spring events, defined as early side-green onset followed by freeze damage, mirror this spatial pattern and are more closely linked to the timing of side-green dates than to freeze-damage frequency. Trends in damage day frequency and severity show notable longitudinal variability, with decreasing trends in the lower OHV flanked by increasing trends in the SGP and VA-NC. Decreasing trends are also observed in northern parts of the UMW and NGP, though significant trends are limited to small areas. These patterns reflect the interplay between spring warm-up timing, phenological development, and seasonal vulnerability, modulated by sub-freezing temperature frequency and severity. The findings highlight the complexity of overwintering crops' responses to climate variability and the need for caution in assessing cold injury risks under future climate scenarios.