[Objective] The aim was to study the characteristics of main vegetation communities in the limestone region of Taihang Mountain,so as to lay foundation for the further improvement of site conditions and the scientific...[Objective] The aim was to study the characteristics of main vegetation communities in the limestone region of Taihang Mountain,so as to lay foundation for the further improvement of site conditions and the scientific breeding of vegetation used to restore the mountain field in limestone region.[Method] Based on the investigation of various vegetation communities in controlled test area,forbidden region and barren hillsides in Daqing Mountain basin,Beishui Valley,Mancheng County,Hebei Province,the difference among controlled region,forbidden region and barren hillsides could be found through data analysis and composite score,and the modes of vegetation communities in controlled region and forbidden region were compared to select predominant species of arbor,shrub and grass in limestone region.[Result] Under the similar site conditions,nutrient content and physical properties of soil in controlled region and forbidden region were superior to those of barren hillsides,and persimmon had high nutrient content and better physical properties compared with oriental arborvitae in controlled region;soil water maintenance and litter characters in controlled region and forbidden region improved more obviously than that of barren hillsides,and shrubbery in forbidden region was the most excellent,arborvitae and persimmon in controlled region the second;the biomass and the coverage rate of vegetation communities in controlled region and forbidden region were higher than those of barren hillsides,and those of shrubbery in forbidden region were better than tussock in closing hill,while persimmon was better than arborvitae in controlled region.The predominant species of arbor,shrub and herbage were obtained through composite score.[Conclusion] From the aspects of soil nutrient,physical properties,soil water maintenance,litter characters,vegetation biomass,canopy density and coverage,controlled region and forbidden region were superior to barren hillsides,and the selection of predominant species of arbor,shrub and herbage considered both ecological and economic benefits.展开更多
Originated in the early 1990s, SCGM(1, m ) c model has enjoyed widespread application in the fields of urban planning, society economy prediction and modal control in recent years. However, none of these applications ...Originated in the early 1990s, SCGM(1, m ) c model has enjoyed widespread application in the fields of urban planning, society economy prediction and modal control in recent years. However, none of these applications have taken account of time lag effects in the modeling process. Aiming at overcoming the defect, the authors introduced time lag items into SCGM(1, m ) c model and developed a SCGM(1, m ) c model with time lag, then discusses in detail some principal problems in the model, such as parameters estimation, model verifying, model prediction, etc. The model was used on a real slope monitoring project and compared with the conventional SCGM(1, m ) c model. The results show an improvement of average models precision from 1.321 to 0.238 and total average of relative prediction errors from 12.41% to 7.98% when the modeling data length ranges from 29 to 48 in the slope monitoring case.展开更多
基金Supported by Hebei Province Natural Foundation (3993173)~~
文摘[Objective] The aim was to study the characteristics of main vegetation communities in the limestone region of Taihang Mountain,so as to lay foundation for the further improvement of site conditions and the scientific breeding of vegetation used to restore the mountain field in limestone region.[Method] Based on the investigation of various vegetation communities in controlled test area,forbidden region and barren hillsides in Daqing Mountain basin,Beishui Valley,Mancheng County,Hebei Province,the difference among controlled region,forbidden region and barren hillsides could be found through data analysis and composite score,and the modes of vegetation communities in controlled region and forbidden region were compared to select predominant species of arbor,shrub and grass in limestone region.[Result] Under the similar site conditions,nutrient content and physical properties of soil in controlled region and forbidden region were superior to those of barren hillsides,and persimmon had high nutrient content and better physical properties compared with oriental arborvitae in controlled region;soil water maintenance and litter characters in controlled region and forbidden region improved more obviously than that of barren hillsides,and shrubbery in forbidden region was the most excellent,arborvitae and persimmon in controlled region the second;the biomass and the coverage rate of vegetation communities in controlled region and forbidden region were higher than those of barren hillsides,and those of shrubbery in forbidden region were better than tussock in closing hill,while persimmon was better than arborvitae in controlled region.The predominant species of arbor,shrub and herbage were obtained through composite score.[Conclusion] From the aspects of soil nutrient,physical properties,soil water maintenance,litter characters,vegetation biomass,canopy density and coverage,controlled region and forbidden region were superior to barren hillsides,and the selection of predominant species of arbor,shrub and herbage considered both ecological and economic benefits.
基金TheNationalNaturalScienceFoundationofChina! (No .497742 0 9)
文摘Originated in the early 1990s, SCGM(1, m ) c model has enjoyed widespread application in the fields of urban planning, society economy prediction and modal control in recent years. However, none of these applications have taken account of time lag effects in the modeling process. Aiming at overcoming the defect, the authors introduced time lag items into SCGM(1, m ) c model and developed a SCGM(1, m ) c model with time lag, then discusses in detail some principal problems in the model, such as parameters estimation, model verifying, model prediction, etc. The model was used on a real slope monitoring project and compared with the conventional SCGM(1, m ) c model. The results show an improvement of average models precision from 1.321 to 0.238 and total average of relative prediction errors from 12.41% to 7.98% when the modeling data length ranges from 29 to 48 in the slope monitoring case.
