ISHS Acta Horticulturae 168: II Symposium on Winter Hardiness in Woody Perennials
AN ATTEMPT TO REANALYSE WINTER INJURY OF APPLE TREES IN FINLAND DURING THIS CENTURY |
| Authors: | E. Kaukovirta, P. Syri |
| Abstract:
Frequently recurring winter injuries in apple orchards result in considerable economic losses in Finland, and render the commercial production of other top fruits scarcely feasible. Luostarinen (1940) estimated that winters causing appreciable injuries tend to recur every 13 – 15 years, but nine such winters have already been recorded this century. When we look for new ways of improving the reliability of fruit production, we naturally examine more closely the nature of overwintering injuries and attempt to determine their cause. After every such injurious winter data have been amassed on the areal extent of injuries, on their nature, and possible causes leading to the injuries have been suggested (Collan 1934, Luostarinen 1940, Meurman 1947, Hårdh 1948, Säkö 1951, Lehtonen 1953, Säkö 1957, Pessala 1967, Säkö & Pessala 1967). For the most part, these studies have concentrated on one particular winter. After the publishing of the above mentioned studies, much new information on the cold hardiness of woody plants, and factors influencing it has become available. In particular, the results of artificial freezing tests carried out in laboratories in Japan, the Soviet Union and USA (Tumanov 1959, Sakai 1959, Howell & Weiser 1970, Weiser 1970) are making valuable contributions to our understanding of these phenomena. We therefore feel it would be both interesting and of practical value to review injuries to apple trees, and possible underlying causes, during the most recent hard winters occurring this century, in the light of the latest studies. | |
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