Classification And Distribution Of Larix Community In Northeast China

In order to better understand the characteristics and geographical distribution of Larix vegetation in Northeast China,and to complete the main research and development work of the northeast part of China Larix Forest,this study takes the sample of Larix forest community in Northeast China as the research object,using quantitative classification and artificial classification method and classification of the Larix community and the preparation of the book according to the "Chinese Vegetation" writing system and norms.On this basis,the following objectives are studied:1)Compilation and research of the northeast part of the Chinese vegetation record "Chinese Larix forest";2)Classification results of three community types(MRT?UPGMA?TWINSPAN)comparison and evaluation;3)The relationship between the distribution of Larix community and environmental factors in Northeast China.The main conclusions are as follows:1)Using the combination of quantity classification and artificial classification,classify 257 plots of Larix communities in Northeast China to establish a classification system of Larix communities in Northeast China,and finally divide the Larix community into two alliances.Larix olgensis and Larix gmelinii alliance;12 Sub-Alliance,Larix gmelinii-Pinus pumila Sub-Alliance,Larix gmelinii-Rhododendron dauricum Sub-Alliance,Larix gmelinii-Ledum palustre Sub-Alliance,Larix gmelinii-Ledum palustre-Mosses Sub-Alliance,Larix gmelinii-Herbs Sub-Alliance,Larix gmelinii-Quercus mongolica Sub-Alliance,Riverside-Larix gmelinii Sub-Alliance,Larix gmelinii-Tatou Carex spp Sub-Alliance,Shitang-Larix gmelinii Sub-Alliance,Mountain-Larix olgensis Sub-Alliance,Slope-Larix olgensis Sub-Alliance and Marsh-Larix olgensis Sub-Alliance,Larix gmelinii alliance is divided into 21 associations,and Larix olgensis alliance is divided into 10 associations.According to the above community classification system,according to the "Chinese Vegetation"writing system and norms,the geographical distribution,community composition,community type,succession and utilization characteristics of different Larix alliance,Sub-Alliance and association were described.To complete the preparation of the Northeast China part of the Larix.2)Using MRT,TWINSPAN and UPGMA methods to classify the populations of Larix olgensis alliance and Larix gmelinii alliance.The results show that the classification result of TWINSPAN is more reasonable,and the choice of method depends on the purpose of the research..The ecological significance of MRT is a specific growth environment that reflects the species of a particular indicator species;the ecological significance of the TWINSPAN method is to reflect the species' adaptation to the environment.The MRT classification is a more appropriate method for the division of large plots or transition zone communities;the TWINSPAN method is the best choice for the distribution and protection of endemic or rare species.As a general method,the UPGMA method is difficult to give a clear ecological meaning,and this method is not a specific method in a specific field,so it can be widely used.3)To further quantitatively analyze the relationship between the distribution of Larix community and the environment,the CCA method was used to study the community ecological relationship of 128 plots in Northeast China.The CCA ranking results showed that for the Larix community in Northeast China,heat and water were important environmental factors for the distribution of Larix community,and showed obvious differences in the distribution of the alliance;for the Larix olgensis alliance,the distribution of Larix community was mainly affected by altitude,slope and coldest month.For the Larix gmelinii alliance,the distribution of Larix community was mainly affected by latitude,water and coldest month.The results of the dominant species showed that the environmental gradient reflected by the distribution of dominant species was highly consistent with the distribution gradient revealed by the community type.