| Coastal shelterbelt had many important ecological functions, such as windbreak, sand fixation, reduce salinity and so on. For urban development and construction coastal shelterbelt should have not only the ecological functions but also reflect the landscape function at the same time, and the landscape shelterbelt is the main form of coastal protection forest in the future, the quality of coastal shelterbelt directly influence the overall construction level of the coastal city. So,it is significant to study the planning and construction of the landscape shelterbelt.In this paper, the shelterbelt distribution, plant resources and soil physical and chemical properties of the coastal shelterbelt were studied by field investigation and interview in Haikou city. On this basis, the planning and construction of the landscape shelterbelt was studied combining with the land development and utilization of the coastal zone in city master plan. The main results as follows: 1.The status and assessment of the coastal shelterbelt in Haikou(1) Mangrove forests and artificial coastal shelter forests were the main coastal shelterbelts of Haikou, mainly including casuarina forest, and some casuarina/ coconut mixed forest. Mangroves are mainly distributed in Yanfeng Town and Sanjiang Town, about 1574.6hm. Artificial shelters mainly included casuarina forests, casuarina/coconut mixed forests, coconut forests and multi-species mixed forests, casuarina forests were the dominant one. Mangrove NR had been established to protect them. It is urgent to unify planning and construction of mainly sandy shore shelter. Now the main problems were:casuarina forests was lack of a certain landscape features for its simple structure of single specie; low landscape ecological functions on the Afforestation of the existing landscape shelterbelt, such as too high ventilation coefficient of shelterbelt, low plant diversity and unreasonable plant community. In addition, there is not a strict coastal defence boundary and no unified planning on afforestation of landscape shelterbelt, all these lead to there is no uniform standard for coastal landscape shelterbelt.(2) There were 181 species in the coastal shelterbelt. including 76 natural species in casuarina shelterbelt, and the dominant species were belonged to Euphorbiaceae, Compositae, Papilionaceae, etc, showing significant tropical characteristics. There is some feature in the natural distribution plants such as few species, simple community structure, strong resistance but lacking landscape features. There were 105 artificial introduction species in landscape shelterbelt, and the dominant species were belonged to Palmaceae, Euphorbiaceae, Apocynaceae,etc, with few native trees and more palm plants.(3) According to the analysis from the soil bulk density, moisture content, pH value, organic matter, total nitrogen, total phosphorus, total potassium, available nitrogen, available phosphorus, potassium and salt content of the soil samples by three different types of forest(casuarina forest, landscape shelterbeltand non-forest land) in coastal of Haikou city, the results showed that:the physical-chemical properties of the soils are confined in a very low levels. The physical and chemical indicators in the forest land are superior to non-forest land, especially organic matter content, casuarina was 0.52-0.92g/kg, no forest land was 0.32-0.57g/kg and landscape forest was 1.27～1.77 g/kg, which showed that coastal protective forest could obviously improve the soil fertilities and the foreign soil greatly improved the soil fertility in landscape shelterbelt; Besides, the forest soil salt content was low, the growth of trees was no longer limited by the salt content in the sandy coastal soil; physical and chemical properties decreased gradually from top to bottom except the soil bulk density, pH value and salt content; The correlation analysis showed that soil bulk density,organic matter content,moisture content had a good correlation coefficient with other nutrient activities, To some extent, these indexes could be used to evaluate the soil fertilities. 2. Studies on the planning and construction of the landscape shelterbelt.(1) According to the current eco-environmental sensitive situation,protection efforts, different development strength on the different coast of Haikou city, and the imperfection in current laws and regulations, it is necessary to use recessional lines solve the conflict between protection and development in coastal area. Based on analysis, the coastal zone of Haikou city is divided into eight different coast, different coast have different requirements on recessional lines range, generally 30-250m from the maximum sea level line to the land.(2) Based on the recessional lines and the results of the shelterbelt, the actual planning and construction, construction goals and overall layout of the coastal landcape shelterbelt were proposed. The planning basis included urban master plan of Haikou city, coastal protection regulation of Hainan Province and investigation and analysis results of this study. To protect the coastal environment and enhance the degree of coastal landscapes as the main principle to built an ecological, recreational, tourism, coastal landscape shelterbelt. (3) According to the objectives and principles of construction in coastal landscape shelterbelt,, the renovation of the coastal shelterbelt and soil improvement measures of sandy coast are raised combined with the status, shelterbelts renovation includes the casuarina forest and coastal landscape shelterbelt. Forest soil improvement is maily by the foreign soil introduction.(4) Selecting suitable species for Haikou coastal shelterbelt construction.87 species were choosed for coastal shelterbelt construction, including 29 arbor species, 23 species of shrub,15 species of herb,5 species of vine and 15 wetland species. This study laid a good foundation for landscape shelterbelt construction on sandy coast in Haikou.(5) Combining these research results, according to requirements on tourism and coastal landscape shelterbelt, the model and plant configuration of the landscape shelterbelt in different width sandy coast were mainly discussed.(6) Designing model of coastal forest landscape. Applying design theory and models of landscape protection forest, the planning and designing of plant scenery about sandy coast protection forest were studied in Gui lin-yang development zone, on the east coast of Haikou city.In a word, by the study on the construction planning of landscape shelterbelt, some suggestions were put forward on planning and construction of landscape shelterbelt. Hopping that these study results can play a role on the future construction of landscape shelterbelt in Haikou city. |
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