The Study On Vegetation Succession Of Hanlongwan Swamp

The northeast region as very important swamp area in our country has rich resource and completed styles. It has the representative in our country's swamp. Because of the continual effect of volcanism from the end of Tertiary to the Holocene, it forms many kinds of volcanic physiognomy. Especially the volcano crater lake and fulgurite lake which formed after the volcano broke forth to provide the negative physiognomy for the swamps development. Water congregate and lake come into being, at the end of the lake's development, it turns to be the swamps.Hanlongwan swamp, Changbai Mountains, Northeast China was chosen for study site. Through the study of mire depositional materials identifying, pollen analysis and the physics and chemistry character of peat, it can be find the regularity which is the process of terrestrial of Hanglongwan, the climate change and the history of vegetation since the Holocene, It aimed at finding the characteristic of change of formation and development of swamps and paleo-environmental change. It will enrich the data of swamps development in northeastern and provides scientific bases for forecasting the environmental changes, development trend of mire, exploitation and protection of mire in distribution regions.The variation history of vegetation in Hanlongwan , for the last 3,500 a.BP is as follows: (1)mixed conifer and broadleaved forest(3,500-3,100aBP) ; (2) mixed conifer and broadleaved forest with priority of broadleaved(3,100-2,250aBP);(3)mixed conifer and broadleaved forest(2,250-2,100aBP);(4)mixed conifer and broadleaved forest with priority of coniferous(2,100-1,500aBP);(5)mixed conifer and broadleaved forest(1,500-750aBP)。(6)mixed conifer and broadleaved forest with priority of coniferous(750-24aBP);(7)mixed conifer and broadleaved forest with priority of broadleaved(24a BP-present)。The climate of Hanlongwan mainly changed from cold to warm, and from wet to dry. The climate change cold-wet from 3,500 a BP;between 2,250 and 2,100a BP,the climate change into warm-dry;during 2,100 to 1,500a BP,the character of the climate turn to wet-cold again;between 1,500 and 750a BP,the climate change into warm and wet;from 750 to 24a BP,the climate again change into wet-cold;the climate change into warm and dry since 24a BP,and from then on ,the character of the climate showed warm-dry.The process of terrestrialization of Hanlongwan lake mainly come through some phases as follows:(1)the phases of the lake's formation (3,300-2,250a BP);(2)the phases of lake's development (2,250-2,100a BP) ; (3)the beginning of terrestrial of Hanlongwan...