Assessment of anticipated performance index of some deciduous plant species under dust air pollution

Green vegetation improvement is an economical strategy to mitigate dust air pollution. The anticipated performance index (API) is considered a main criterion to select the suitable plants of urban forests. API is calculated by taking air pollution tolerance index (APTI) and socio-economic and biological aspects into account. In the present work, API of four current deciduous tree species in urban areas of Iran was evaluated. The seedlings were soil-dusted by a dust simulator in plastic chambers at levels of 0, 300, 750, and 1500 μg/m³ at intervals of 1 week for 70 days. At 750 and 1500 μg/m³ dust concentrations (DCs), greatest dust collection capacity was observed with Morus alba and the lowest one with Melia azedarach. Increasing DC declined APTI of all species. At 750 μg/m³ DC, only Morus was tolerant, but at 1500 μg/m³ DC, this species and Melia were categorized as intermediate, and Celtis caucasica and Fraxinus rotundifolia as sensitive. Morus was assessed as a good performer under two higher DC. Celtis was recognized as a moderate under 750 μg/m³ DC and poor performer under 1500 μg/m³ DC. Thus, Celtis can be considered as a biomonitor for air quality or as sink for dust in high dusty areas because of its high capacity of dust deposition. At two higher DCs, Fraxinus and Melia showed very poor and poor performance; planting these species in high dust areas is not recommended. In contrast, Morus is the most suitable tree species for urban green spaces in dusty regions, due to its high dust collection capacity and high APTI and API values.