Episode 43 - David Hewitt helped research the book Philadelphia Trees: A Field Guide to the City and the Delaware Valley

David Hewitt has been working with plants, animals, soils, and water
for more than twenty-five years, starting when he began working on
small farms in upstate New York.  He has served in a variety of roles
at a number of Philadelphia institutions, including the Wagner Free
Institute of Science, and as a lecturer at the University of
Pennsylvania and a research associate in the Department of Botany at
the Academy of Natural Sciences.  He was an AAAS Science and Technology Policy Fellow in
Washington, DC, working in agricultural policy. David has an A.S. from
the Community College of Philadelphia, a B.A. in  biology from the
The University of Pennsylvania and a Ph.D. from the  Department of
Organismic and Evolutionary Biology at Harvard University.