Spatial Pattern Optimization Of Water Source Forests In Baiyangdian-Daqing River Basin

Water resource is a necessary condition for the construction and development of xiong’an new area.As the water conservation area of xiong’an new area,it is of great significance to analyze the spatial pattern of vegetation in the upper reaches of Baiyangdian-Daqing River Basin,identify the problems of water source forest,optimize the spatial pattern of water source forest,and improve the water conservation capacity of the upper reaches of Baiyangdian-Daqing River Basin.Based on the principles of plant ecology and phytogeography,this paper uses geospatial information technology to study the water source forest in the upper reaches of the Baiyangdian-Daqing River Basin.The data of soil geology,topography,vegetation quadrat,meteorology and remote sensing were obtained.The water source conservation function of the study area was evaluated,and four optimization models were put forward.The optimization results were simulated,and all optimization models were successful It can reduce water consumption or increase water yield in different degrees,and provide theoretical support for the optimization of water conservation function of upstream water source forest.The specific conclusions are as follows:(1)According to invest model calculation,the present situation of water production in Baiyangdian-Daqing River Basin is 3.58×10~9m~3,and the present situation of water conservation is 1.71×10~8m~3.The areas with high water conservation function are mainly distributed in Fuping County,Yi County,Laiyuan County,Quyang County,Shunping County,Tang County,etc.(2)Aiming at the problem of slow growth or even stagnation caused by unsuitable plants,the optimization model of precise replacement of unsuitable plants was proposed.According to the accurate suitability analysis of plants,the unsuitable area of plants is 240.41km~2,which is Pinus tabulaeformis,Platycladus orientalis,Robinia pseudoacacia and other communities;the unsuitable plant communities are accurately replaced by Platycladus orientalis,Prunus armeniaca,Quercus variabilis,Ailanthus altissima,Larix principis rupprechtii,Vitex negundo and Hippophae rhamnoides.(3)In view of the serious problem of soil and water loss under coniferous forest after canopy closure,the optimization model of reducing the irrational canopy closure of coniferous pure forest was put forward.According to the calculation of reasonable canopy density by multiple linear regression,the area of pure Pinus tabulaeformis forest with unreasonable canopy density is 135.68 km~2,the undergrowth vegetation is sparse,and the soil erosion is serious;the canopy density of pure Pinus tabulaeformis forest is reduced according to the altitude range,which is 0.70-0.75 in high mountain area,0.65-0.7 in low mountain area,and 0.6-0.7 in middle mountain area.(4)Aiming at the problem of a large number of high water consumption plants in the upstream mountain area,the paper puts forward the replacement optimization mode of high water consumption plants,summarizes the water consumption rules of plants,and concludes that the high water consumption plants are Poplar,Koelreuteria,etc.,with an area of 211.56km~2;the high water consumption plants are replaced by low water consumption plant communities such as Pinus tabulaeformis,Quercus variabilis,Vitex negundo,etc.(5)Aiming at the serious problem of soil and water loss caused by bare land without vegetation cover,the optimal vegetation restoration model of bare land block was put forward.The area of bare soil is1756.38 km~2,which is 4.08%of the large drainage area and 9.41%of the mountain area,and the bare soil is restored to communities of Robinia pseudoacacia,Ailanthus altissima,Platycladus orientalis,Pinus tabulaeformis,Vitex Negundo,Spiraea,Hippophae rhamnoides,Betula platyphylla,Quercus variabilis and Quercus variabilis.(6)After the optimization of various spatial patterns,the vegetation coverage in the upper reaches of the mountain area increased,the proportion of forest land coverage in the large watershed increased by4.69%,the water consumption decreased,the water production increased by 3.10×10~8 m~3,the water conservation increased by 8.66%,and the water conservation increased by 1.34×10~7 m~3,the proportion of promotion was 7.84%,and the effect of spatial pattern optimization was good.