Abstract: A lot of tree residues(wood fossil)were found under the pumice layer in alpine and subalpine vegetation in the Changbai Mountain.The residues of Betula ermanii and Pinus pumila distributed from 2050 m to 2160 m in the south slope.Based on ¹⁴C dating, the residues were covered by a volcanic eruption happened 1580?70 years(408?70 AD)ago.Pinus Pumila communities disappeared after volcanic eruptions.From 1200 m to 1300 m asl in the east slope,the tree residues are dominated by Larix olgensis,as well as Picea jezoensis var.komarovii,Abies nephrolepis and Betula platyphylla etc.The palaeovegetation is similar to the current.In 2150 m asl of the east slope where the current vegetation is tundra,the only species of residues found under the pumice is Larix olgensis.Because of volcanic eruptions,the timberline lowered from original 2200 m to current 2000m asl.The forest from 2000 m to 2200 m asl was replaced by tundra after the events.The timberline is getting higher,but very slow.In the bare land of volcanic rock, vegetation succession model is.lichenes-moss-vascular plant communities,and the pumice bare land is occupied directly by vascular plants.