Forest Community Dynamics In Burned Area In Great Xing’an Mountains Based On LANDIS PRO

In 2017,the"5.2"forest fire in Bilahe of Great Xing’an Mountains in Inner Mongolia burned an area of 11500 hm~2,which was considered as a particularly seri ous forest fire.Burned area is located in the national key ecological function area,which bears the important ecological functions of water conservation,soil and water conservation,biodiversity maintenance and so on,and is of great importance to th e ecological security of this area.Therefore,the vegetation restoration and communi ty succession after forest fire disturbance have attracted much attention.The traditio nal field investigation method to research on large scales of time and space of the burns vegetation dynamics,In this thesis,the spatial intuitive forest landscape mode l LANDIS PRO 7.0 was used to simulate the forest community dynamics in Bilahe,Inner Mongolia,under three different conditions of natural,harvest and artificial re generation after harvest in 300 years,aim to reveal the forest succession law and t he changing trend of landscape pattern after forest fire disturbance and the response model to human disturbance.The main conclusions were as follows:(1)field standard samples from 22 species in 2017-2019 chest area field surve y data and LANDIS PRO model corresponding to the year,the corresponding locati on of tree species chest area simulation value of single factor analysis of variance,Pearson correlation analysis results show that the LANDIS PRO model simulated va lues and the error of the measured values in the acceptable range,the credibility of simulation results is credible.(2)Under natural conditions,The changing trend of the cross-sectional area of breast height of tree species in the burned area was as follows:in the early perio d(100 years),the proportion of White birch,black birch,Aspen continued to incre ase until the peak and then decreased slowly,while the growth trend of Xing’an L arch,Mongolian oak,Pinus sylveira and Amur corktree increased slowly.In the mi ddle period(100-200 years):the growth trend of Xing’an larch becomes faster,and then gradually decreases after reaching the peak,while other species stop growing or continue to decrease,and the range of change gradually decreases with time.L ate stage(200-300 years):The community was in a stable state without significant change.(3)With vegetation restoration,the community in the mildly burned area gradu ally stabilized after 70 years of succession,while the community in the moderately and severely burned area stabilized after 130 years and 150 years,respectively.In the early stage of succession,the age class structure of each tree species changed greatly,and the proportion of the younger stand increased while the proportion of t he older stand decreased.The changes of landscape pattern showed that the number of patches increased,the patch shapes tended to be complex,and the patch spatial distribution tended to be scattered.As time goes on,the tree species age class str ucture tends to be stable,the landscape fragmentation and heterogeneity decrease gr adually,and the landscape tends to be homogenized.(4)the current cutting scheme significantly reduced the vegetation area and ext end species succession cycle,the succession prophase older forest area ratio greatly reduced,tree age class structure changed significantly in the process of succession,delay the time of the stability of the age class structure,and increase the degree of landscape fragmentation,increased the species number of patches,and on the lan dscape distribution is more dispersed,which may lead to raise of landscape heterog eneity.The current artificial regeneration scheme can obviously promote the vegetati on restoration before and during succession,but it cannot effectively alleviate the n egative effect of logging on landscape pattern.