干旱区城市绿化树种在截留沙尘、降低大气颗粒污染物浓度、改善城市生态环境方面发挥着不可替代的作用。本文对新疆南部典型绿洲城市——阿克苏市不同功能区的法国梧桐(Platanus acerifolia)、新疆杨(Populus alba var.pyramidalis)、...干旱区城市绿化树种在截留沙尘、降低大气颗粒污染物浓度、改善城市生态环境方面发挥着不可替代的作用。本文对新疆南部典型绿洲城市——阿克苏市不同功能区的法国梧桐(Platanus acerifolia)、新疆杨(Populus alba var.pyramidalis)、圆冠榆(Ulmus densa)和小叶白腊(Fraxinus sogdiana)的叶片平均滞尘量进行了对比,量化了叶片自身因素、自然因素、人为因素对单位滞尘量的影响程度,并对这3个因素对滞尘量的影响进行了权重分析。结果表明:对同一功能区而言,树种平均滞尘量次序为法国梧桐(5.54g·m-2)、新疆杨(2.93g·m-2)、圆冠榆(2.50g·m-2)、小叶白腊(1.36g·m-2)。对不同功能区而言,水泥厂绿化树种叶片平均滞尘量最大,其次为居民区、公园区、交通区、工业区、城郊防护林区。影响树种滞尘能力的3个因素中,人为因素权重最大,贡献率为0.89;自然因素其次,贡献率为0.45;而叶片自身因素的影响最低,贡献率为-0.13。可见,在防止沙尘污染时应尽量减轻人为活动所引起的二次扬尘。展开更多
Growth quality of urban trees should include exterior growth quality, interior growth quality and anti-natural-calamity ability. To determine the whole growth quality of a tree, it is necessary to observe exterior cha...Growth quality of urban trees should include exterior growth quality, interior growth quality and anti-natural-calamity ability. To determine the whole growth quality of a tree, it is necessary to observe exterior characters of every part of the tree carefully. The hollows of the roots caused by decay or rot can be detected by Resistograph, and the hollows of the trunks can be detected by Resistograph and a stress wave meter.展开更多
A comprehensive European overview of recent and ongoing research in Europe has been carried out within the framework of COST Action E12 'Urban Forests and Trees', a pan-European research network. This paper pr...A comprehensive European overview of recent and ongoing research in Europe has been carried out within the framework of COST Action E12 'Urban Forests and Trees', a pan-European research network. This paper presents some of the main findings of a comparative analysis of 20 individual country reports. The analysis shows that research on urban forests and urban trees in Europe has a wide scope and is rather fragmented and uncoordinated. Universities and state research institutes, mostly with a forestry or...展开更多
As the process of urbanization advances across the country, so does the importance of urban forests, which include both trees and the soils in which they grow. Soil microbial biomass, which plays a critical role in nu...As the process of urbanization advances across the country, so does the importance of urban forests, which include both trees and the soils in which they grow. Soil microbial biomass, which plays a critical role in nutrient transformation in urban ecosystems, is affected by factors such as soil type and the availability of water, carbon, and nitrogen. The aim of this study was to characterize residual forest patches and open fields in residential areas in the City of Knoxville. A field study was conducted to investigate tree species diversity and determine spatial and temporal soil characteristics along an urban-to-rural gradient. Tree diversity did not differ significantly for residential urban and rural plots in Knoxville, Tennessee. Biologically, there was no indication that soils were affected by tree diversity, in terms of soil microbial biomass C/N along an urban-to-rural gradient in Knoxville residential plots. Rural soils did differ physically from urban soils, cation exchange capacity (CEC) and soil moisture content (GSM). Similarly, physical soil properties such as bulk density, both urban and rural sites were negatively correlated with tree diversity. Results indicate that although the urban-rural gradient is subject to urban environmental stressors, the urban ecosystem is resilient in maintaining the ecosystem functions of more natural systems.展开更多
文摘Growth quality of urban trees should include exterior growth quality, interior growth quality and anti-natural-calamity ability. To determine the whole growth quality of a tree, it is necessary to observe exterior characters of every part of the tree carefully. The hollows of the roots caused by decay or rot can be detected by Resistograph, and the hollows of the trunks can be detected by Resistograph and a stress wave meter.
文摘A comprehensive European overview of recent and ongoing research in Europe has been carried out within the framework of COST Action E12 'Urban Forests and Trees', a pan-European research network. This paper presents some of the main findings of a comparative analysis of 20 individual country reports. The analysis shows that research on urban forests and urban trees in Europe has a wide scope and is rather fragmented and uncoordinated. Universities and state research institutes, mostly with a forestry or...
文摘As the process of urbanization advances across the country, so does the importance of urban forests, which include both trees and the soils in which they grow. Soil microbial biomass, which plays a critical role in nutrient transformation in urban ecosystems, is affected by factors such as soil type and the availability of water, carbon, and nitrogen. The aim of this study was to characterize residual forest patches and open fields in residential areas in the City of Knoxville. A field study was conducted to investigate tree species diversity and determine spatial and temporal soil characteristics along an urban-to-rural gradient. Tree diversity did not differ significantly for residential urban and rural plots in Knoxville, Tennessee. Biologically, there was no indication that soils were affected by tree diversity, in terms of soil microbial biomass C/N along an urban-to-rural gradient in Knoxville residential plots. Rural soils did differ physically from urban soils, cation exchange capacity (CEC) and soil moisture content (GSM). Similarly, physical soil properties such as bulk density, both urban and rural sites were negatively correlated with tree diversity. Results indicate that although the urban-rural gradient is subject to urban environmental stressors, the urban ecosystem is resilient in maintaining the ecosystem functions of more natural systems.
