Study On The Stability Of Forest Landscape Patches Coupling Network Structural

The stability of forest system affects the complex large multi-functional system, restrict the competition between forest and interaction energy, material, species diversity of forest plays an important role. But how to come up from the perspective of the whole forest system study of the stability of the forest, there is no a systematic way. This study from the perspective of landscape science, according to the advantage of tree species, age group will stand division of landscape patches, edge effect between patches and plaques as coupling dynamic factors, from Taoyuan county of hunan province second small class can be derived from the vector diagram forest landscape patch coupling 53, then choose the 20 coupling system by complex network is abstracted into forest landscape patch coupling network, network index number of vertices and betweenness to conduct a comprehensive analysis on the stability of the structure of the coupling network, build model related to network structure stability. According to the features of network index combined with the actual production of the forestry, forest landscape patches of the coupling system management measures are put forward, the main research contents and research results are as follows:(1) The selection of network node number on network structure stability analysis. This article selects different 10 network node number, according to the associated with the node number of forest landscape stability plaques coupling network structure model:from Giant-2 to Tiny-1 network breakdown threshold value of 0.3259,0.3101,0.2834,0.273,0.2484,0.2159,0.1945,0.1962,0.1583, 0.1574, the decreasing trend, that of forest landscape patches of coupling system plaques more to less than the number of patches structure is more stable; With the increase of the number of network vertices, the breakdown threshold value to increase the rate of decrease gradually, when plaque number increased to a certain extent, the structure stability of the coupling system no longer change. According to the characters of complex network structure, number of vertices in the network is used to measure the structural stability of the network, and then from a new perspective to explore the forest landscape structure stability.(2) The selection of network node betweenness on network structure stability analysis. This article selects 10 medium-sized network node number is roughly same, betweenness cumulative distribution curve through the network and the network breakdown threshold contrast found that the structure of the network stability and betweenness distribution, curve starting point for the closer it gets to the point of origin, the greater the stability of the network, the more far away from the origin, the network is more vulnerable. Forest landscape according to the ideal associated with referral number distribution network structure stability plaques coupling model: according to the selected medium network, its ideal betweenness distribution network structure stability model g (x) with b in the value of 157.29, and k as a minimum, the more network betweenness distribution curve tends to be the ideal curve, the greater the stability of the network structure, at this point in the network node betweenness uniform distribution, plaque and plaque close-knit, energy and material exchange frequently.(3) Forest landscape patch coupling system management measures are put forward. Using number distribution related to the number of vertices, and interfaces related network structure stability of the model, a simulation to the increasing number of vertices, balance the node betweenness distribution can effectively improve the stability of the forest landscape patch coupling network. Specific management measures:When the coupling system surrounding forest landscape patches exists deforested or wasteland, young forest can be updated with the different native tree species, which further increases the coupling system on the edge of the plaque number; When the forest landscape patches in the coupling system stand poor quality big patches, can through the thinning rezoning plaque, such as, in turn, reforestation, build large patches in the local "mixed"; When forest landscape patch coupling when there is a "hole" in the system, can according to the site conditions, be suitable to fit the tree will be "empty" the location of the replanting of sapling, in certain areas of site conditions of poor can planting shrubs.