Study On The Major Characters And Stability Of Managed Ecosystem In Huangyangtan

Desertification is one of biggest environment questions in the world, which also is the main manifestation of desertification in the north of our country. In recent years, the sandstorm occurred frequently, which has do a great harm to ecological envioment. Yanghe sandy land is one of the important dustsources of Beijing and Tianjing sandstorm source, located at Zhangjiakou area, Hebei province.To combat the wind sand disaster, in recent year this area has made ecological construct cosmically and gained favorable effects. This paper take Huangyangtan sandy land as example, based on a mass of research and observation, Using grey relational analysis method, from the physical properties of soil, soil chemical properties, the growth of forest, forest plant diversity, comprehensive quantitative evaluation of different types of plantation stability, and for the region to improve the status of Plantation stability of the measures and silvicultural measures. The result indicated:(1) Through determinaty and analysis the Huangyangtan physical properties of soil, we can see: the different types of plantations, The comparison of soil aggregate composition is very greatly. In the composition of the soil particles, 1～0.1 mm particles formed in the percentage of between 34.63 to 96.01 percent, the soil is composed of machinery as a percentage of the maximum. Soil particles larger than 0.05 mm of the particle composition of the total of 87.98 percent, this component can be seen from the Huangyangtan region of sandy soil in plantations still quite serious. We selected in the water holding capacity of soil and retention indicators, soil bulk density in 1.43～1.68 g/cm~3 between the soil in the field capacity between 14.94 to 24.88 percent, water retention and retention is relatively weak, and the soil containing Water only between 3.74 to 6.68 percent, relatively low moisture levels, and between all levels of soil moisture changes were not evident.(2) Huangyangtan region due to relatively large annual sandstorms, litter the ground floor of relatively small, resulting in the area of soil organic matter content of low organic matter content of the highest kind for the 5th kind of poplar and apricot mixed for 7.812 g / kg, the smallest on the 14th for the kind of Amorpha fruticosa X the Scotch Pine mixed shrub land of organic matter content of 1.488 g / kg. Through comprehensive evaluation on the 5th kind of poplar and apricot mixed forest is the highest correlation coefficient of soil nutrients, soil nutrient status of the best.(3) Through the Huangyangtan different plantation growth, the average growth of trees of Populus popular s and Populus alba L.var.pyramidalis are the largest, and still in the growth stage of the age class of small oriental arborvitae, black locust, elm's crown The average annual growth rate of crown is the largest. On the 10th of the kind of Scots pine, the average growth of plants, stand-year average and the average annual growth of net productivity are the highest. Scots Pine Forest through a comprehensive evaluation of the best growth conditions, but the stand density is relatively small.(4) Through the different types of plantation forest diversity of plant species, forest plantations that Huangyangtan a single level, herbs only during the rainy season when the re-germination, and less variety in the investigation of the 16 samples And a total of 31 kinds of plants, under Section 15. Mainly concentrated in the legume, Compositae, the three branches of the grass family. In a kind arguably the largest number of plant species for the first three Feipeng, Lespedeza, green bristlegrass. Huangyangtan region and a total of 92 branches, 288 genera and 527 kinds. This see: Huangyangtan Plantation under the plant diversity is also low, due in large plantations in the introduction of native species, to raise plantations of species diversity.(5) Evaluated the plantations with ash association coethcient analysis, the result that the plot 5, Poplar×A pricot mixed forest and plot 10 Amorpha fruticosa forest, are the most stability forest stands. The relatively stability plantations are the polt 1 poplar×Robinia pseudoacacia mixed forest, plot 12 Platycladus orientalis of 17 years, plot 7 Poplar, plot 11 Caragana korshinskii Kom, plot 6 elm trees of 13 yeas,plot 3 elm trees of 7 years, plot 4 Poplar of 9 year, plot 15 Populus popular s, plot 16 Populus alba L.var.pyramidalis,The relatively middle stability plantations are plot 2 Robinia pseudoacacia of 5 years, plot 9 Elaeagnus angustifolia L, plot 13 Platycladus orientalis of 7 years, plot 14 Amorpha fruticosa×the Scotch Pine, The instability plantations is plot 8 Salix psammophila.(6) Aim at the plantations in Huangyangtan, take measures by water and site management, optimize community structure, man-promoted natural regeneration, humanity factor, enhancing the stability of plantations.