In this presentation, Alessio Fini discusses an experiment that began in 2011 to evaluate the effects of different pavements on the growth and health of two urban tree species: Fraxinus ornus (Manna ash) and Celtis australis (European hackberry). Biometric and physiological measurements have been made since 2012. Listen to the Science of Arboriculture podcast and then take the accompanying CEU quiz to check your knowledge. (A, U, M, T, Bp)