“…There is no doubt, however, that they also have other important functions such as providing a setting for recreation (Gundersen et al, 2006), contributing to the overall well-being of citizens (O'Brien, 2005), improving climate in cities, regulating air exchange, f iltering polluting substances, reducing wind speeds, muffling noise, and reducing atmospheric carbon dioxide concentrations, etc. (Akbari et al, 2001;Nowak and Crane, 2002;Nowak et al, 2004Nowak et al, , 2006.…”