Chamber and Field Evaluations of Air Pollution Tolerances of Urban Trees

Abstract

Results are presented for a study of the relative air pollution tolerances of 32 urban-tree cultivars as determined by both chamber fumigations and field exposures. Tolerances to ozone and sulfur dioxide, alone and in combination, were determined using short-term, acute doses administered while the plants were inside a plastic fumigation chamber located inside the Cary Arboretum greenhouses. In a follow-up study still underway, representatives of the same cultivars were outplanted at four locations in the greater New York City area. To date, only oxidant-type injury has been observed on trees in the field plots. Cultivars tolerant to all chamber and field exposures were Acer platanoides 'Cleveland,' 'Crimson King,' 'Emerald Queen,' 'Jade Glen,' and 'Summershade'; Acer rubrum 'Autumn Flame' and 'Red Sunset'; Acer saccharum 'Green Mountain' and 'Temple's Upright'; Fagus sylvatica 'Rotundifolia'; Fraxinus pennsylvanica 'Summit'; and Ginkgo biloba 'Fastigate' and 'Sentry.' Cultivars sensitive to ozone as determined by the chamber and field tests and that may serve as bioindicators of the presence of ozone were Gleditsia triacanthos inermis 'Imperial' and Platanus acerifolia 'Bloodgood.'