Finding sustainable energy resources is essential to face the increasing energy demand.Trees are an important part of ancient architecture but are becoming rare in urban areas.Trees can control and tune the pedestrian...Finding sustainable energy resources is essential to face the increasing energy demand.Trees are an important part of ancient architecture but are becoming rare in urban areas.Trees can control and tune the pedestrian-level wind velocity and thermal condition.In this study,a numerical investigation is employed to assess the role of trees planted in the windward direction of the building complex on the thermal and pedestrian wind velocity conditions around/inside a pre-education building located in the center of the complex.Compared to the previous studies(which considered only outside buildings),this work considers the effects of trees on microclimate change both inside/outside buildings.Effects of different parameters including the leaf area density and number of trees,number of rows,far-field velocity magnitude,and thermal condition around the main building are assessed.The results show that the flow velocity in the spacing between the first-row buildings is reduced by 30%-40% when the one-row trees with 2 m height are planted 15 m farther than the buildings.Furthermore,two rows of trees are more effective in higher velocities and reduce the maximum velocity by about 50%.The investigation shows that trees also could reduce the temperature by about 1℃around the building.展开更多
Change in plant phenology is one of the most sensitive ecological responses to climate warming. Little information is known about the effects of climate warming on phenology of urban tree species in the northern fores...Change in plant phenology is one of the most sensitive ecological responses to climate warming. Little information is known about the effects of climate warming on phenology of urban tree species in the northern forest of China. In this study, we investigated the phenological characteristics of the main tree species in the urban forest of Shengyang City in China and the correlation between phenology and atmospheric temperature from the discontinuous data during past 42 years over three time periods(from 1962 to 1965, 1977 to 1978, and 2000 to 2005). The results showed that the annual average temperature in Shenyang City showed an increasing trend and increased by 0.96℃ from 1962 to 2005 due to climate warming. The germination phenology of the urban trees was negatively correlated with the temperature in winter and early spring. The leafing phenology was mainly influenced by the temperature in spring before leafing. Influenced by climate warming, the germination, leafing, and flowering phenologies of this urban forest in 2005 were 14, 13, and 10 days earlier than those in 1962, respectively. We inferred that further warming in winter might prolong the growing season of urban trees in the northern forest of China.展开更多
Although small in size, PM25 can do great harm to the environment, and city greening trees can reduce PM2.5 pollution to a certain extent. This paper reviewed the mechanism of city greening trees to reduce PM2.5 pollu...Although small in size, PM25 can do great harm to the environment, and city greening trees can reduce PM2.5 pollution to a certain extent. This paper reviewed the mechanism of city greening trees to reduce PM2.5 pollution, screening and classification of green land allocation model of PM2.5 reducing greening trees, and made prospect on how to construct the evaluation index system of PM2.5 re- ducing greening trees and urban green land allocation.展开更多
An Oracle8i-based approach is proposed to manage the integrated databases oflarge CyberCity. This approach consists of three schemes: ① a special R+-tree index is designed toaccelerate spatial retrieving, in which th...An Oracle8i-based approach is proposed to manage the integrated databases oflarge CyberCity. This approach consists of three schemes: ① a special R+-tree index is designed toaccelerate spatial retrieving, in which the bounding boxes of local regions have no intersection andall leaf nodes of the R+-tree (geometry records ) have no repetition; ② different data compressionalgorithms are adopted to compress the digital elevation models, 3D vector models and images, suchas LZ77 lossless compression algorithm for compression of vector data and JPEG compressionalgorithms for texture images; ③ in order to communicate with Oracle8i database, a CyberCity GIS.spatial database engine (SDE) is designed. On the basis of this SDE prototype a case study is done.展开更多
Urban greening trees intercept the migration of atmospheric particulate matters near the ground, and it is difficult for the particulate matters trapped by foliage to re-elevate, thus reducing the hafm to humans....Urban greening trees intercept the migration of atmospheric particulate matters near the ground, and it is difficult for the particulate matters trapped by foliage to re-elevate, thus reducing the hafm to humans. The dust-capturing ability and foliar dust size charactetistics of different greening trees are different In addition, the dust capturing of trees is distutbed by many factors such as sel natural and human factors. The foliar dust and natural dustfaJl in 11 common, tree species in Aksu, Northwest China were collected to analyze tihe particle size distribution diacacteristics,and obtain the concentrations of PM^ and PM10. The results showed that Pktanus acenfolia, Populus alba var. pyramidaJis and Uhnus densa. had high foliar dust attachment density and strong particle-capturing capacity,while Elaeagnus angustifoliaL., Pyrns sinldangensis, Sophora japonica L. had low foliar dust attachment density. The foliar PMZ5 and PM10 contents were highest in E. ongustifolia （0.68%） and Vitis vinefcra （3.59%）, tespectively. The volume fraction of fine partides was small in natural dustM and was kige in foliar dust The median of foliar dust particle size followed tiie descending ordei： industrial area 〉 transportation hub area 〉 residential area 〉 clean area; and the median of natural dustfall particle size followed the descending order： dear area 〉 transportation hub area 〉 industrial area 〉 residential area. There was a big difference between the two.展开更多
The research aimed to apply phytoindication for controlling air pollution with chlorine and lead in Yerevan. The research was performed between 2005 and 2008.5 arboreous species were studied： Robinia pseudoacacia L.,...The research aimed to apply phytoindication for controlling air pollution with chlorine and lead in Yerevan. The research was performed between 2005 and 2008.5 arboreous species were studied： Robinia pseudoacacia L., Fraxinus excelsior L., Populus alba L., Morus alba L. and Uitis vinifera L.. The research showed that arboreous plants growing in the city accumulate chlorine and lead. Chlorine concentrations in all 5 species varied from 0.50% to 1.77%, and the maximum value was found in Robiniapseudoacacia L., exceeding the control by 3.6 times. As for the level of lead in plants, the concentration varied between 1.64-7.65 mg/kg, and the maximum rate exceeds the background （2.0 mg/kg） by 3.8 times. The authors produced a schematic map of chlorine distribution all over the city, territory, and detected the most polluted zones. According to the data the autbtors collected, only 3 of 5 studied species displayed high intake rate and tolerance to lead and chlorine pollution： Robinia pseudoacacia L.. Fraxinus excelsior L. and Populus alba L. Thus, the authors advise these species for planting in Yerevan. The results of this research were used by the Municipality of Yerevan for functional tree planting in the city.展开更多
文摘Finding sustainable energy resources is essential to face the increasing energy demand.Trees are an important part of ancient architecture but are becoming rare in urban areas.Trees can control and tune the pedestrian-level wind velocity and thermal condition.In this study,a numerical investigation is employed to assess the role of trees planted in the windward direction of the building complex on the thermal and pedestrian wind velocity conditions around/inside a pre-education building located in the center of the complex.Compared to the previous studies(which considered only outside buildings),this work considers the effects of trees on microclimate change both inside/outside buildings.Effects of different parameters including the leaf area density and number of trees,number of rows,far-field velocity magnitude,and thermal condition around the main building are assessed.The results show that the flow velocity in the spacing between the first-row buildings is reduced by 30%-40% when the one-row trees with 2 m height are planted 15 m farther than the buildings.Furthermore,two rows of trees are more effective in higher velocities and reduce the maximum velocity by about 50%.The investigation shows that trees also could reduce the temperature by about 1℃around the building.
基金National Natural Science Foundation of China(No.31270518,31170573)National Science and Technology Major Project(No.2012ZX07202-008)National Science and Technology Support Program(No.2012BAC05B00)
文摘Change in plant phenology is one of the most sensitive ecological responses to climate warming. Little information is known about the effects of climate warming on phenology of urban tree species in the northern forest of China. In this study, we investigated the phenological characteristics of the main tree species in the urban forest of Shengyang City in China and the correlation between phenology and atmospheric temperature from the discontinuous data during past 42 years over three time periods(from 1962 to 1965, 1977 to 1978, and 2000 to 2005). The results showed that the annual average temperature in Shenyang City showed an increasing trend and increased by 0.96℃ from 1962 to 2005 due to climate warming. The germination phenology of the urban trees was negatively correlated with the temperature in winter and early spring. The leafing phenology was mainly influenced by the temperature in spring before leafing. Influenced by climate warming, the germination, leafing, and flowering phenologies of this urban forest in 2005 were 14, 13, and 10 days earlier than those in 1962, respectively. We inferred that further warming in winter might prolong the growing season of urban trees in the northern forest of China.
基金Supported by the Planning Project for the Practical Creativity Training for College Students of Institution of Higher Education of Jiangsu Province in 2014(Sujiaobangao[2014]No.8)the Science and Technology Planning Project of Nantong City(HS2014025)+2 种基金the First Micro-financial Support Project for Ecological Construction of Nantong City(Tonghuan[2014]No.33)the Project for Venture Philanthropy of Nantong City(Tuantongweilian[2015]No.D11)the Crosswise Project of Jiangsu Misho Ecological Landscape Co.,Ltd~~
文摘Although small in size, PM25 can do great harm to the environment, and city greening trees can reduce PM2.5 pollution to a certain extent. This paper reviewed the mechanism of city greening trees to reduce PM2.5 pollution, screening and classification of green land allocation model of PM2.5 reducing greening trees, and made prospect on how to construct the evaluation index system of PM2.5 re- ducing greening trees and urban green land allocation.
基金Project supported by the National Key Basic Research and Development Program (No. 2002CB312101) the National Natural Science Foundation of China (No.40001017).
文摘An Oracle8i-based approach is proposed to manage the integrated databases oflarge CyberCity. This approach consists of three schemes: ① a special R+-tree index is designed toaccelerate spatial retrieving, in which the bounding boxes of local regions have no intersection andall leaf nodes of the R+-tree (geometry records ) have no repetition; ② different data compressionalgorithms are adopted to compress the digital elevation models, 3D vector models and images, suchas LZ77 lossless compression algorithm for compression of vector data and JPEG compressionalgorithms for texture images; ③ in order to communicate with Oracle8i database, a CyberCity GIS.spatial database engine (SDE) is designed. On the basis of this SDE prototype a case study is done.
基金Sponsored by Natural Science Foundation of Xinjiang Uyghur Autonomous Rrgion(2017D01B15)
文摘Urban greening trees intercept the migration of atmospheric particulate matters near the ground, and it is difficult for the particulate matters trapped by foliage to re-elevate, thus reducing the hafm to humans. The dust-capturing ability and foliar dust size charactetistics of different greening trees are different In addition, the dust capturing of trees is distutbed by many factors such as sel natural and human factors. The foliar dust and natural dustfaJl in 11 common, tree species in Aksu, Northwest China were collected to analyze tihe particle size distribution diacacteristics,and obtain the concentrations of PM^ and PM10. The results showed that Pktanus acenfolia, Populus alba var. pyramidaJis and Uhnus densa. had high foliar dust attachment density and strong particle-capturing capacity,while Elaeagnus angustifoliaL., Pyrns sinldangensis, Sophora japonica L. had low foliar dust attachment density. The foliar PMZ5 and PM10 contents were highest in E. ongustifolia （0.68%） and Vitis vinefcra （3.59%）, tespectively. The volume fraction of fine partides was small in natural dustM and was kige in foliar dust The median of foliar dust particle size followed tiie descending ordei： industrial area 〉 transportation hub area 〉 residential area 〉 clean area; and the median of natural dustfall particle size followed the descending order： dear area 〉 transportation hub area 〉 industrial area 〉 residential area. There was a big difference between the two.
文摘The research aimed to apply phytoindication for controlling air pollution with chlorine and lead in Yerevan. The research was performed between 2005 and 2008.5 arboreous species were studied： Robinia pseudoacacia L., Fraxinus excelsior L., Populus alba L., Morus alba L. and Uitis vinifera L.. The research showed that arboreous plants growing in the city accumulate chlorine and lead. Chlorine concentrations in all 5 species varied from 0.50% to 1.77%, and the maximum value was found in Robiniapseudoacacia L., exceeding the control by 3.6 times. As for the level of lead in plants, the concentration varied between 1.64-7.65 mg/kg, and the maximum rate exceeds the background （2.0 mg/kg） by 3.8 times. The authors produced a schematic map of chlorine distribution all over the city, territory, and detected the most polluted zones. According to the data the autbtors collected, only 3 of 5 studied species displayed high intake rate and tolerance to lead and chlorine pollution： Robinia pseudoacacia L.. Fraxinus excelsior L. and Populus alba L. Thus, the authors advise these species for planting in Yerevan. The results of this research were used by the Municipality of Yerevan for functional tree planting in the city.
