CENTRE ON THE PROBLEMS OF ECOLOGY AND PRODUCTIVITY OF FORESTS

RUSSIAN ACADEMY OF SCIENCES

I.T. Kishchenko, I.V. Vantenkova Seasonal Growth of White Birch in Northern Karelia // Forest Science (Lesovedenie). 2011. No 4. С.48-52.

The investigations were conducted in northern Karelia (northern taiga); the objects were 67-78-year-old bilberry-forbs and grass-cowberry birch forests. Similarity and differences in the birch growth in different forest types were revealed. The growth of vegetative organs in the aboveground tree parts follows the definite subsequence. Shoots of the second order grew the first (late May); after 2-3 days, leaves appeared, and in several days, stem wood began to grow. The highest increment of shoots was observed in late June-early July, of leaves at the beginning - middle of July, stems - in the middle - end of July. The growth of shoots, leaves, and stems ends in late July, August, and late August, respectively. The intensity of growth was higher in the bilberry-forbs birch forest than in the grass-cowberry birch forest. In the former forest, the daily increment of shoots, leaves, stems was greater by 85, 96, and 78%, respectively, than that in the latter one. The more intense and long-term growth of birch trees under optimal environmental conditions leads to increasing their annual increment. In the bilberry-forbs birch forest as compared to the grass-cowberry birch forest, the length of shoots, leaf are, and width of annual rings were greater by 18, 25, and 50% greater, respectively. The growth of shoots, leaves, and stems in the bilberry-forbs birch forest begins by a week earlier and ends by two weeks later than in the grass-cowberry birch forest. In the former forest, the growth of shoots, leaves, and stems lasts for a longer time by 13, 10, and 9 days than in the latter forest.

birch, vegetative otgans, forest type, seasonal growth.

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