Joel Sternfeld’s iconic photograph of Ailanthus trees in the Flyover, May 2000. Photo: Joel SternfeldAilanthus altimissa growing wild in West Side Rail Yards near 34th St. Entry, July 2011Betty Smith’s A Tree Grows in Brooklyn, with an Ailanthus altissima, or “tree of heaven”Tom Smarr, head of horticulture for Friends of the High Line, in interim walkway August 2013 holding Staghorn sumac (right hand) and Ailanthus altissimo (left). Ailanthus was always present all over the wild High Line, but sumac was found only in this one place near 34th streetStill here: ailanthus altimissa — or is it sumac? — growing in a scrap yard at 28th Street, with the Flyover just steps away, July 2012