Research On Structure And Benefit Of The Windberaking And Fining Sand Of Desert In Southern Xinjiang

In this study,sand of desert in Southern Xinjiang forest for the study,using field investigation and laboratory test analysis method of combining and using correlation analysis,regression analysis,mathematical analysis and AHP comprehensive evaluation model and other observational and experimental data analysis.From the species composition,hierarchical organization,reasonable density start a systematic study of the southern region of sand sand-fixing forest structure and benefit,it is intended to provide some theoretical guidance for the sand-fixing forest of construction,improving the local ecological environment in southern sandy area.The main conclusions of this study are:(1) Taking the approach of level analysis, factor analysis and comprehensive evaluation model to comprehensively evaluate the vegetation site factors of southern Xinjiang desert in areas, according to the site environment,plant physiological ecology characteristics chosen the suitable tree species, by using the gray interrelated analytical method to evaluate the main species suitability, the order of the Tree species is Populus euphratica>Populus alba>Elaegnus angustifolia>Ulmus pumila>Fraxinus velutina.And the order of the shrub is Tamarix chinensis>Calligonum mongolicum>Hippophae rhamnoides>Cerasus humilis>Haloxylon ammodendron>Lycium chinense.(2) According to the structure of existing vegetation types,growth conditions and protection and other factors and site type comprehensive analysis,taking into account economic efficiency and protection screening structure for different types of protective forest habitats southern sandy area, including six kinds of sand-fixing forest,farmland protection forest 12 species,five kinds of timber, four kinds of forests,nine kinds of road shelterbelts.(3) Tree forest shelterbelt system through porous windbreak performance and degree of forest, forest age, with the most relevant higher, while seasonal changes also affect an important factor in the effectiveness of windbreak shelterbelts.Sparse forest protection best protection from the forest to the high band within 10 ~ 13 H, which is good windbreak forest area on the leeward side with high 3 ~ 5H.Sand frontier zone shrub density woodlots, and filling high performance sub-index is a key factor in the impact wind.Transition zone and inside the oasis, the distance between main Shelter belt should be the main forest tree height determined based 11 H.General shall be the main Shelter belt pitch 100 ~ 150 m, secondary belts appropriate spacing 150 ~ 200 m.The main Shelter belt is to play a major role in forest protection, to which should be the main victims of the prevailing wind direction or perpendicular to the wind direction, as far aspossible consistent with the farm roads, irrigation and drainage channel direction.If the affected rivers and other terrain is not perpendicular to the main wind direction, allowing <45° angle between the secondary belts to main Shelter belt should be at right angles.(4) Based on the study area in different seasons air temperature measurements show that in spring and autumn shelterbelts are to improve temperature 0.29℃ and 0.2℃,while in the summer,you can cool down0.76℃,which cool the most obvious internal oasis of cool up to 1.14℃.The shelterbelt regulation of temperature plays an important role in agricultural production.Shelterbelt on soil improvement is a relatively slow process,but in the process of plant growth through material circulation changed physical and chemical properties of soil,improve soil structure,soil fertility gradually improved.Sand frontier zone due to the moisture conditions and Sand Fixation on biomass and productivity are relatively low.(5)Taking the analytic Hierarchy Process southern area is mainly sand shelterbelt system for comprehensive benefit evaluation of screening.And through SPSS software for data processing dimensionless,to determine each index weight coefficient.The results show:Three partitions ecological comprehensive assessment score followed. Midtown district> Internal Oasis> sandstorm frontier zone.The ecological benefits of tree with Populus, Populus alba, shrub tamarisk mixed composite score is 38.79 and41.81 in the sand frontier zone and midtown district.Comprehensive evaluation of ecological benefits of tree,shrub and mixed into 38.93 of Populus and sea buckthorn in the internal Oasis.Best reflects the effectiveness of the region are mixed tree, shrub and shelterbelt structure.