Image analysis and coummunity monitoring on coniferous forest dynamics in Changbai Mountain.

The structure and dynamics of coniferous forests in Changbai Mountain were studied at different spatial scales, including ground survey of permanent plots and analysis of multitemporal satellite images. Plot-scale examinations showed that the mortality rate was 7% - 9%, and the recruitment rate was 18% - 20% per 10 years. Species composition changed over time. Picea jezoensis var. microsperma, Abies nephrolepis and Betula ermanii presented a self-maintaining capability, because they could regenerate under canopy. Larix olgensis was a pioneer species and could regenerate only in open land or gaps. This species played an important role by providing conditions for the regeneration of spruce and fir. The tree density in the mature forest was 1 000 stems x hm(-2) for trees bigger than 3 cm in diameter, which showed no significant variations among different stands. Landsat TM images were used for detecting the cover changes from 1984 to 1997. Large scales of wind throw were detected by this approach. Based on t he analysis of radiance changes at the landscape scale, the pixel number of the disturbed area was similar to that of the succeeding stands, suggesting that the forest was in a state of equilibrium. Fine gaps, however, were difficult to identify with the TM data because of its coarse resolution. The mosaic structure ofthe subalpine vegetation was characterized by scattered larch patches. At the landscape level, the vegetation was in a stable stage.