Optimization On Spatial Distribution Of Coastal Protective Forests In Dongshan Island Based On 3S Technology

Coastal protective forest system is an important content of the ecological construction,while it is an important part of the mitigation system construction of coastal areas too.Due to its special geographical position and location advantage, coastal regions play an important position and role In the development of the nation.Accelerating the coastal protective forest system construction, constructing efficient and reasonable coastal protective forest system, and strengthening the defense against natural calamities ability of coastal regions, are urgent strategic tasks of ecological construction of China.On the basis of environmental problems of Dongshan island,technology needs of the protective forest system, and geography, economic and social conditions of Dongshan island,the paper applies advanced theory, methods and techniques,according to the field investigation material,using different periods remote sensing image of the study area,extracted time-space distribution project information of Dongshan island coastal protective forest,aimed at different period protective forest type function change and existing problems,raise optimized adjustment and establish evaluation index system ,then get the optimal configuration mode proportion.The paper aimed at improving the resist the ecological risk ability of islands, providing a relatively stable ecological environment for the local economic and social development and making the shelter-forest function gets maximize.The main research contents and conclusions as follows:(1)On the basis of landform features of Dongshan island, the paper combining unsupervised classification and supervision classification and layered classification method to classify geophysics of remote sensing image of 2001, 2004 and 2007,and classification accuracy of three phase are more than 80%,and Kappa coefficient are larger than 0.8.Explain the remote sensing project classification is source of remote sensing information, it can improve classification effect. (2) Established remote sensing image classification system of the coastal protective forest,chose a single land change dynamic degrees, comprehensive land dynamic change degrees, transfer contribution rate ,then adopt classification and superposition method to make analysis of land dynamic change of 2001 to 2007 of study area.The results showed that land use type change trend of Dongshan island is that the area of sand, cultivated land and unused decreased. Sand and unused land have the biggest changes. Land of residents and woodland area are increasing, and the change of resident land is larger than woodland. And the area of the waters remains unchanged. According to the changes of land use situation of dongshan island in 2004-2007, land use structure of Dongshan island would reach stable state in around 2040.(3) Through screening coastal protection configuration mode, sum up eight main configuration mode.And on the basis of investigation visit, laboratory analysis,expert consultation ,and literature review, established evaluation index system, calculated the best proportion of each configuration mode under the highest in comprehensive benefit condition.(4)Based on the analysis of protective forest optimization disposition theory, based on protective forest type function and the existing problems, focuses on optimized adjustment of depth protection forest tries,select configuration index, such as woodland height, woodland width, woodland spacing, drafty coefficient, winds weaken coefficient, belts average individual nutrition area, and strains spacing, using GIS spatial analysis technology divided shelter-forest into three-level allocation,and calculated area and forest coverage rate of different levels forest tries and configuration.the results showed that: the forest coverage rate of the primary forest tries, secondary forest tries, triple forest tries respectively are 2.16%, 1.58% 2.34%. In the constraints condition of optimized configuration , the forest coverage rate is improved greatly.(5)Put forward the principle of taking protective existing forest keeping original state.Build dike woodland in some dike frontier, construct protective forest system of Dongshan island consists by dike woodland, backbone belts, deep woodland, protective forest tries, village forest.And generates related configuration diagram used geographical information system (GIS).