新疆阿克苏市绿化树种滞尘能力及影响因素

Dust Retention Capacities of Urban Trees and the Influencing Factors in Aksu,Xinjiang,China

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。

Urban trees in arid land oasis cities have been playing very important purification role in capturing dust particles,reducing airborne pollutant concentrations and improving of urban ecological environment.In this paper,dust retention capacities of Platanus acerifolia(Ait.),Populus alba var.pyramidalis Bunge,Ulmus densa Litw.,Fraxinus sogdiana Bunge at different functional areas of typical oasis city Aksu in Southern Xinjiang were examined under different weather conditions.Human factors,natural factors and tree's own factors which mainly determine the dust retention capacity of urban greening trees were quantitatively analyzed.The results showed that P.acerifolia(Ait.)performed strongest dust retention capacity(5.54 g·m-2)for the same functional area,followed by P.alba var.pyramidalis Bunge(2.93 g·m-2),U.densa Litw.(2.50 g·m-2),F.sogdiana Bunge.(1.36 g·m-2).For the different functional areas,urban trees in Cement Factory demonstrated highest dust retention capacities,followed by residential areas,parking areas,traffic areas,industrial areas,suburban shelterbelt areas.Among the three influencing factors,human factors was the greatest in contributing dust accumulation on tree leaves,contribution rate was 0.89,tree's own factors was the weakest,contribution rate was-0.13.This indicated that human-induced secondary dust pollution should be focused on dust prevention measurements.