The peculiarities of winter dormancy state transition of gymnosperm and angiosperm arboreal plants

Using the method of thermally induced changes in the needle fluorescence zero level to determine the duration and depth of arboreal plant winter dormancy it is discovered that needles of Picea obovata and Abies sibirica come out of hibernation faster than Pinus sibirica, Pinus sylvestris and others. The damage of the Picea obovata needle photosynthetic apparatus may occur in spring season, when after a few days of warm weather plants prematurely get out of winter dormancy.