Nina Bassuk describes the way she'll start off with a new group of students: asking them to draw a simple picture of a tree. In this anecdote all of the usual suspects show up - trunks, branches, leaves and even a bird or two to represent wildlife. “But,” she says, “what is glaringly absent from almost all of these tree portraits are the life-supporting root systems.” Bassuk, Professor and Program Leader of the Urban Horticulture Institute at Cornell University, goes on to explain what is wrong with these pictures - and what an eye-opening experience it is.