H. Dennis RyanH. Dennis Ryan

Professor Emeritus


Primary Interests

Dr. H. Dennis P. Ryan is an Arborist and was the Program Coordinator of the Arboriculture/Urban Forestry Program at the University of Massachusetts , Amherst . Prior to joining the faculty at the University, Dr. Ryan was Executive Director of Forestry and Horticulture for the Parks Department of the City of New York . In addition to municipal experience, he also worked as a commercial arborist for ten years. Dr. Ryan’s consulting work is in the area of tree and arboricultural accidents and he was Chairperson of the ANSI Z-133 Arboricultural Safety Committee.

Current Projects

  • Hazard tree management systems
  • Arboricultural safety issues and accidents

Selected Recent Publications

Ryan, H. D. & B. Kane, 2012. “Trees, Storms & Utility Systems”. TREE CARE INDUSTRY 23 (12) 22 – 24.

Ryan, H. D., 2012. “Are all tree accidents TCI accidents?”. TREE CARE INDUSTRY 23 (9) 53.