Silva Fennica : quarterly issues : 30(2–3) : sa3023159.htm

Ilkka Leinonen, Tapani Repo & Heikki Hänninen. 1996.

Testing of frost hardiness models for Pinus sylvestris in natural conditions and in elevated temperature

Silva Fennica 30(2–3): 159–168

Two dynamic models predicting the development of frost hardiness of Finnish Scots pine (Pinus sylvestris L.) were tested with frost hardiness data obtained from trees growing in the natural conditions of Finland and from an experiment simulating the predicted climatic warming. The input variables were temperature in the first model, and temperature and night length in the second. The model parameters were fixed on the basis of previous independent studies. The results suggested that the model which included temperature and photoperiod as input variables was more accurate than the model using temperature as the only input variable to predict the development of frost hardiness in different environmental conditions. Further requirements for developing the frost hardiness models are discussed.

climatic warming, dynamic models, photoperiod, Scots pine, temperature

University of Joensuu, Faculty of Forestry, PO Box 111, FIN-80101 Joensuu, Finland. Fax +358 13 151 4444, E-mail

Received 4 September 1995 Accepted 14 May 1996
ISSN 0037-5330