Althouse Arboretum primarily seeks to preserve and collect native Pennsylvania species.  On one of their trails, the Penn's Woods Trail, the trees were specifically selected to represent the various species that would have inhabited this area at the time William Penn walked through these woods.  Trees were presented to GreenAllies by the Pennsylvania Horticultural Society.  These trees were then planted by volunteers and labeled.  It is the vision of GreenAllies to have a short trail that displays many of the tree species that were originally abundant in our woods.