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[B-4.2.3 Study of the Effects of Environmental Factors on the Forest Dynamics in Northern Siberia(Final Report)]

[Contact Person]

TAKENAKA, Akio
Global Environment Research Group
National Institute of Environmental Studies
l 6-2 Onogawa, Tsukuba, 305, Japan
Phone +81-298-50-2474 Fax +81-298-55-2569
e-mail takenaka@nies.go.jp

[Total Budget for FY1994-1996]

15,470,000 Yen (FY1996 5,167,000 Yen)

[Abstract]

　To analyze the dynamics of forests in the northern Siberia, we investigated the age structure, spatial distribution pattern and growth pattern of larch trees growing in the northern part of taiga forests in the eastern Siberia region. The study sites were located in the lower reaches of the Lena and Kolyma rivers, and in the lower and middle reaches of the Enisei river. In some of the study sites, we found an obvious tendency for aggregation of the trees in a scale of a few meters, which suggests patchy distribution of favorable conditions for tree establishment. However, the condition needed for the seedling establishment is unknown. Spatial heterogeneity of a larger scale of tens to hundreds of meters were also observed in the forest structure. In each of the study sites, the distribution of the tree age was not uniform: there had been 'good periods' and 'bad periods' for new tree establishment. The 'good periods' did not coincide among sites as closes as less than 1km from each other. In the middle reach of the Enisei river, synchronous pattern of shoot extension growth were found among the larch trees. The synchrony indicates environmental control of the extension growth. A preliminary analysis indicated that the extension growth of a year depends on the amount of photosynthetic production stored in the previous year.

[Key Words]

Forest structure, Height growth, Larch forest, Tree age