ROOT FROST HARDINESS OF AMENITY BROADLEAVED SEEDLINGS

Abstract

Summary The root frost hardiness of four species of amenity broadleaved trees was assessed during the winter of 1993/94. This was repeated with four different species during 1994/95. Fine roots were sampled every three weeks and subjected to a range of freezing temperatures. Damage was assessed by electrolyte leakage. There were significant differences in frost hardiness among species and sampling dates. Frost hardiness was more closely related to soil temperature than to air temperature or rainfall. Some species responded to short term fluctuations in soil temperature and this response was more pronounced during periods of hardening and dehardening than in mid-winter. The degree of species resistance to frost damage over both years' experiments increases in the following general order: wild cherry < Norway maple, small-leaved lime, rowan and common ash < silver birch and common beech < pedunculate oak.