Effects of ozone on chinese trees

Abstract

This chapter reviews the effects of elevated ozone on tree species in China, based on the results of studies in the past two decades. The high ozone concentration in summer in most parts of China has induced typical ozone symptoms in urban and mountain forest tree species. In experiments using open-top chambers, elevated ozone affected the growth, gas-exchange rate, foliar microscopy, antioxidant systems, and biogenic volatile organic compound (BVOC) emissions in trees. The effects of ozone on biomass accumulation depended on the ozone concentration, tree species sensitivity, and exposure duration. The ozone uptake of individual tree species was also investigated by the sap flow technique. Further studies were conducted on the interactions between O3 and other environmental change factors, such as increasing CO2 concentrations, increased nitrogen deposition, and drought. Future needs for research include the development of an O3 flux model for the most widely used tree species and the assessment of ozone removal by urban forests on a regional and a national scale.