Research On The Shelter Nets Construction Of Shanghai Farm

The farmland shelterbelt optimize model were studied after investigated theShanghai farm forestry. We bring forward the planning and design of the main treespecies and forest community configuration in the residential area ecologicalrecreational forest and road landscape forest. The results are as follows:1. Farmland shelterbeltAverage increase quantum of aboveground biomass per year per area for PolarTrees were highest, Metasequoia plyptostroboide were in the middle, while Robiniapseudoacacia were slowest. The accumulate speed order of biomass belowground werePolar Trees＞Metasequoia plyptostroboide＞Robinia pseudoacacia. Total biomass growthper year were Polar Trees (6-year)＞Metasequoia plyptostroboide (22-year)＞Robiniapseudoacacia (32-year), which indicated that the Polar trees have quickest biomassaccumulate speed, while the quickest biomass accumulate speed for Robiniapseudoacacia was slowest.The growth of height for Polar tree were far quickly than other two species. Thegrowth of per year and in successive years for Robinia pseudoacacia and Metasequoiaplyptostroboide were 0.94m/a and 0.85m/a, 0.99m/a and 1.24m/a, respectively. Whilethe growth of per year and in successive years for Polar tree could reach 2.20m/a and2.87m/a. In the sixth year, the average growth of lignum cubage for Polar tree reached0.0262m3/a, which were 20.96 and 21.83 times large than Robinia pseudoacacia and Metasequoia plyptostroboide. The growth speed order for three trees were Polar Trees＞Metasequoia plyptostroboide＞Robinia pseudoacacia.The soil volume weight, salt content, organic matter content, PH in each layer ofthree farmland shelterbelts were little than bottomland, and the soil total content andmean also little than bottomland, which indicated that each farmland shelterbelt modelcould meliorate soil quality. In soil, the distributing of some indexes has certainorderliness, i.e. organic matter gradually decreases from the top down, while soilvolume weight and PH gradually increase. The meliorated effects for each soil indexwere different due to different species or different forestation times.The average porosity for Metasequoia plyptostroboide and Robinia pseudoacaciashelterbelt were similar, between 30% and 33%, and it called porosity structure belt,which have better windbreak effects. While the average porosity for Polar tree werehighly reached to 48.46%, and called ventilation structure belt. Its windbreak effectswere inferior to other belts. In the three shelterbelts, the windbreak effects order wereMetasequoiaplyptostroboide＞Robinia pseudoacacia＞Polar Trees.Among the forestation tree species in Shanghai farm farmland shelter belts, theadjustability to climate and soil were best for Robinia pseudoacacia, which endurebarren, salt and alkali. Amorpha fruticosa also have better adjustability. Both are goodspecies to protect slope and soil. To forestation in Wanzhuang region, we commendRobinia pseudoacacia. In other renewal and building regions, we may consider usingPolar trees as main species, and mixed it with other species at the same time. The higharbor such as Polar tree, Robinia pseudoacacia, Bischofia Polucarpam Airy Shaw, andMetasequoia plyptostroboide may select as superstratum tree. The Sabina virginiana A.,Ligustrum lucidum Ait., Chinese hackberry and Amorpha fruticosa may select assub-arbor or shrub. Building shelterbelt with complex structure could sufficientlyexerted the defend efficiency of belt. At the same time, mixture of different speciescould reduce the harm of plant diseases and insect pests. 2. Residential area ecological recreational forestThe planning and layout of residential area ecological recreational forest in theShanghai farm should according to the systematic, ecological, recreational andeconomic principle. Which were subdivided as landscape ecological forest, naturalrecreational forest and ecological sightseeing forest by these principles. The planningand layout optimized the ecological function of forest and could building a sight pattenin which human and nature harmonious coexist. All these accord with the need of newfarm building. The mainly species and forest community were also planed and designedaccording these principles.The keystone of building residential area ecological recreational forest are improveresidential environment, have certain ecological benefits, process civilizationconnotation. The purpose is building a near-natural forest ecological system withecologically environmental benefits. The building of ecological recreational forest alsocould satisfy the resident needs.3. Road landscape forestThe road landscape forest could connect the forests, which in insulated state, andconnected the point and side, consequently guarantee the integer and function ofShanghai farm shelter nets. Meanwhile, by green-porch construction and analysis fromdifferent visual angle, form an undulate, seriate forest-top-line and forest-edge-line. Inthe important sight area, pinpoint the sightseeing of plant collocation. There are 5 framestyles (mixed arbor and arbor, arbor and shrub, arbor, sub-arbor and shrub, shrub andshrub, mixed many tree species) in planning and design of road landscape mixedforests.