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作者

来源

URBAN FORESTRY & URBAN GREENING,Vol.21,P.16-28

语言

英文

关键字

Sodium chloride; De-icing salts; Airborne salt; Roadside trees; Leaf sodium accumulation; Urban soil salinity; Soil pH; DEICING SALT; ALKALI STRESSES; COLD-HARDINESS; SALINITY; SEEDLINGS; ACCUMULATION; TOLERANCE; RESPONSES; HEALTH; PLANTS

作者单位

[Equiza, M. A.; Cirelli, D.; Senorans, J.; Zwiazek, J. J.] Univ Alberta, Dept Renewable Resources, Edmonton, AB T6G 2E3, Canada. [Calvo-Polanco, M.] SupAgro INRA CNRS UM2 UMR 50042, Biochim & Physiol Mol Plantes, Pl Viala, F-34060 Montpellier 2, France. [Wartenbe, M.; Saunders, C.] City Edmonton, POB 2359, Edmonton, AB T5J 2R7, Canada. Zwiazek, JJ (reprint author), Univ Alberta, Dept Renewable Resources, Edmonton, AB T6G 2E3, Canada. E-Mail: janusz.zwiazek@ualberta.ca

摘要

The application of de-icing salts for winter road maintenance is recognized as a major contributor to the decline of urban trees. We conducted a long-term monitoring program across several locations in the City of Edmonton (Alberta, Canada) to evaluate the impact of roadway salt application on tree species widely planted in boulevards and right-of-ways: Ulmus americana, Fraxinus pennsylvanica, Pinus contorta, and Picea glauca. Soil and leaf samples were collected from a total of 16 sites over six years. There were four sites selected for each tree species: three mid-to high-traffic roadside sites that received regular winter maintenance and one non-serviced site (control). Sampling was performed three times per year from late spring to late summer. Airborne salinity was assessed in four locations at different distances from the road. In 50% of the roadside sites, soil electrical conductivity (EC) values exceeded 2 dS m(-1). Soil pH in all of the roadside sites was also significantly higher than in the control sites, with values ranging from 7.6 to 8.5. In all four species, trees growing in sites with high soil EC had increased leaf Na concentrations and reduced leaf chlorophyll concentrations. Among the airborne monitoring sites, Na deposition in high traffic locations was over four-fold higher than those measured in the control location. Furthermore, Na levels remained relatively high at 20-50 m from the main road. Our data suggest that while soil salinity is among the main stressors affecting roadside trees in Edmonton, salt spray deposition may also have a significant impact on trees located close to high vehicle traffic areas and dense road networks. Our study highlights the importance of collecting data over several years and from multiple locations to account for the spatial and temporal heterogeneity of the urban environments in order to better evaluate the impact of road salt application on urban trees. (C) 2016 Elsevier GmbH. All rights reserved.