1999 Volume 16 Issue 1 Pages 83-97
This article first reviewed the distribution of the forests of the boreal zone of northeastern Asia. Then it arranged the forest boundaries on the basis of the alternation of the ecological characteristics of the dominant species, and discussedthe conditions for the establishment of the forest boundaries. Five major species forming their own dominant forests occurred ; Quercus mongolica, Pinus koraiensis, Picea jezoensis, Larix gmelinii, Betula ermanii, varying both in shade tolerance (tolerant, intolerant) and in leaf character (deciduous broad leaves, evergreen needle-shaped leaves, deciduous needle-shaped leaves). The distribution of the forests in the zone was complex, differing from that in the boreal zone of Europe and northeastern America. The most noticeable feature in the forest distribution was that shade-intolerant species such as P. koraiensis, L. gmelinii and B. ermanii make their own forest. L. gmelinii covers vast areas of interior and northern part of the zone, associated with the distribution of the permafrost. Six major forest boundary types lies within the zone corresponding to the complex forest distribution; Q. mongolica-P. jezoensis, P. koraiensis-P. jezoensis, P. jezoensis-L. gmelinii, P. koraiensis-L. gmelinii, P. jezoensis-B. ermanii and B. ermanii-L. gmelinii. The physical environments of the zone such as sharp gradient of the continentality-oceanity of the climate, wide distribution of the permafrost and the prevalence of the mountainous physiography in the coastal area together promote these forest boundaries by different manners, resulting in the complex forest distribution of the zone, and in the prevalence of L. gmelinii.
