The Pennsylvania-Delaware Chapter of the International Society of Arboriculture was founded in 1960. The purpose of this organization is to foster a greater appreciation for shade trees and to promote the science, technology, and practice of professional arboriculture in the states of Pennsylvania and Delaware.

There are currently over eight hundred members in the chapter including commercial, consulting, municipal, and utility arborists, researchers and educators, horticulturists, and individuals interested in the care of trees and landscapes.