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Climate extremes such as cold spells are becoming more frequent as climate variability increases. However, few studies have evaluated the impacts of winter cold spells on forest cover, tree growth and leaf and sapwood non-structural carbohydrate (NSC) concentrations. We analyzed changes in tree cover using remote sensing data and compared the radial growth of coexisting and defoliated <i>Pinus halepensis</i> trees and non-defoliated <i>P. halepensis</i> and <i>Pinus pinaster</i> trees. We also compared NSC concentrations in leaves and sapwood of defoliated and non-defoliated <i>P. halepensis</i> and <i>Quercus ilex</i> trees. In January 2021, a rapid drop in temperatures led to minimum values (−21.3 °C) in eastern Spain and triggered canopy defoliation in several planted (<i>P. halepensis</i>) and native (<i>Q. ilex</i>) tree species. The cold spell led to a decrease in forest cover in the most defoliated stands and reduced radial growth of defoliated <i>P. halepensis</i> and sapwood NSC concentrations in <i>P. halepensis</i> and <i>Q. ilex</i>, particularly starch. Prior to the cold spell, defoliated <i>P. halepensis</i> trees significantly (<i>p</i> < 0.05) grew more (2.73 ± 1.70 mm) in response to wetter winter conditions than non-defoliated <i>P. halepensis</i> (2.29 ± 1.08 mm) and <i>P. pinaster</i> (1.39 mm) trees. Those <i>P. halepensis</i> individuals which grew faster at a young age were less resilient to the winter cold spell in later years. The study stands showed a high recovery capacity after the cold spell, but the Mediterranean drought-avoiding <i>P. halepensis</i> was the most affected species.