Winter Injury to Apple Trees, 1980-1981

Abstract

Serious winter injury and tree losses occurred to apple cultivars in eastern Ontario and Quebec following the winter of 1980-81. On December 24, 1980, a rapid drop in temperatures from -9°C to -28°C over a 16 hr. period occurred at the Smithfield Experimental Farm (S.E.F.), Trenton, Ontario. Further, a 30 year record low temperature of -37°C was recorded on January 4,1981. Below nor mal temperatures continued through January (Table 1). Above normal temperatures in February and March resulted in an early spring. Frosts occurred on April 19 (-6°C), 21 (-5°C) and 22 (-4°C) when McIntosh buds were at the 12 mm green stage.