PALEOVEGETATIONAL AND PALEOCLIMATIC CHANGES IN HA'NI LAKE, JILIN SINCE 5 kaBP

According to the spore pollen analysis results of 85 core samples from Ha'ni Lake,the history of vegetation and environment can be divided into four stages as follows:① StageⅠ(5 112~3 784 aBP):Broadleaved trees dominated in this stage, and the climate was warm and wet;② Stage Ⅱ(3 784~1 380 aBP):The coniferous trees dominated during the whole stage, hydrophytic herbaceous plants disappeared, and the climate changed to be cold and dry;③ Stage Ⅲ(1 380~994 aBP):The percent of coniferous trees continued to increase but hydrophytic herbaceous plants began to appear, suggesting that the climate was colder but a little more humid; ④Stage Ⅳ(994~0 aBP):The diversity of plants was great, and the pollen sedimentation rate of hydrophytic herbaceous plants obviously increased, so the climate changed to be more humid.