The Dynamic Simulation Of Forest Landscape Pattern Based On LANDIS

Dynamic changes of forest landscape will lead to differences in forest ecological system within the material,energy and bio distribution in space and motion.Due to the longtime of forest succession cycle and wild range of space,traditional field observation methods cannot be effective monitoring the dynamic changes of the forest succession.With the development of technology,the computer model simulation became an effective method.Through the forest landscape pattern dynamic simulation research,we can reveal the process and rules of forest landscape structure change,and provide guidance for the protection of the ecological environment and sustainable forest management.This study is integrated with forest landscape visualization and forest landscape quantitative spatial analysis method,which has realized quantitative and qualitative visual analysis of forest landscape pattern.By using LANDIS PRO 7.0 model to simulated dynamic change of forest landscape under natural succession and harvesting mechanism and landscape index method to analyze the forest landscape change in species composition and spatial and temporal pattern of 150 years,the visualization of dynamic simulation of forest species at different periods is achieved.The main research contents and results are as follows:(1)The paper expatiates the research status of both domestic and international from three aspects:forest landscape pattern research,dynamic simulation of forest landscape and forest landscape visualization and points out the shortage existing in the current research.The relevant theory and technology of the main research contents are introduced,such as forest landscape pattern index,the principle of the LANDIS PRO 7.0 model and the building method of the virtual forest environment.(2)Integrate the landscape index with the independently-developed forest landscape visualization system software,VisForest,realizing quantitative and visual analysis of forest landscape pattern.Based on the data from the second class survey of forest resources in 2013,Minhou Baisha state forest farm was taken as an instance.According to dominant tree species,forest landscape were classified and landscape composition,patch characteristics and landscape heterogeneity etc.were analyzed.The results showed that Cunninghamia lanceolate forest,Pinus massoniana forest,Pinus elliottii forest,Schima superba forest and non-forest land are the dominant landscape types in Minhou Baisha state forest farm.The overall landscape types are abundant and the heterogeneity level is relatively high.Moreover,as the seclusion cincture tree species,Schima superba in the majority with small area,long and narrow patch.Schima superba's shape index and fractal dimension number is the largest and patch shape is complex and irregular.Integration of virtual forest environment with landscape index calculation model is the simulation technology of the combination of intuitive judgment and quantitative data analysis,simulation technology,provides an intuitive and interactive display.(3)Take the second class survey of forest resources of Minhou Baisha state forest farm as the main data source.Using LANDIS PRO 7.0 model to simulate the long-term dynamic changes of forest landscape pattern in natural succession and harvesting mechanism in both cases to achieve the simulation of change of trees stand visualization at different succession period.According to the percentage of the area of species,the species' average patch area,patch numbers,aggregation index,etc.,we analyzed the trend of landscape pattern change and the species composition change of each age class in the study area.The results showed that the average patch area and aggregation degree of each species were significantly decreased through harvesting,and the number of patches and patch density were increased.It indicated that the harvest led to a certain degree of fragmentation of forest landscape,significantly reducing the area proportion of mature forest species and increasing the proportion of the young forest area,while the influence of Eucalyptus was not obvious.