Over at Wired they note that:
Brooklyn web developer Jill Hubley ... made a map pinpointing 592,130 street trees (52 species!) in New York as they were documented in the tree census of 2005.
Going on to note that not every tree is a good fit for ever location, author Neel V. Patel notes that one popular tree is New York perfect.
"Many people think Callery Pears give off an aroma reminiscent of rotting fish, chlorine, or semen, so it more-or-less fits in with NYC’s odor profile."
The trouble, of course, is that the Callery Pear (more often called the Bradford Pear) "is susceptible to losing limbs or keeling over during strong winds, heavy snowfall or ice storms." (Thanks Lucas M.!)