The aim of this study was to find out the planting vigour of Scots pine (Pinus sylvestris L.) stored over the winter either in winter storage mainly in the temperature of 4 – -6 °C or in nursery beds. The experimental planting included about 4,500 of 2+1 transplants in Northern Finland. In spring 1965 the control plants were lifted in the spring before budbreak and stored in closed bags in a cold store, in the following year the control plants were lifted in June when the growth had started.
Winter storage of pine transplants in a cold store, tightly closed into bags for the major period, did not, according to the results, increase plant mortality as compared to lifting in the spring. Soaking the stored-plant roots did not affect plant mortality. Mortality was rather small in all treated lots and probably more dependent on planting site and other local factors.
No consistent difference on the leader growth, needle length, bud number and plant grade was found between the plants stored over winter and those lifted in the spring. Sealing the plants into tight bags for winter proved to be suitable method, efficiently preventing water shortage in the plants. No moulds or fungal diseases were found in the plants. In the exceptionally cold 1965–1966 winter, temperature in the cold store sank to -15 °C, but in spite of the temperatures below the recommended storing temperature, the plants survived well. The reason was that the plants froze slowly in the fall and thawed out slowly in the spring.
The value of vigour grade in predicting plant-characteristic development proved to be good, and predicted plant development also in the following year fairly well.
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