H. Dennis RyanH. Dennis Ryan

Professor Emeritus


Phone: 413-253-3769

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.

Kane, B. & H.D. Ryan. 2012. “Rigging Ropes & Hitch Strength”.  TREE CARE INDUSTRY  23 (3) RS1 – RS5.

Julius, A., B. Kane, M. Bulzachelli, and H.D.P. Ryan. Investigation of Compliance with Safety Standards in the New England Tree Care Industry. National Occupational Injury Research Symposium, October 2011, Morgantown, WV. Refereed proceedings.

Rines, D., B. Kane, H. D. Ryan, and D. Kittredge. 2010. Urban Forestry priorities of Massachusetts tree wardens. Urban Forestry & Urban Greening. Vol. 9. # 4: 295–301.

Rines, D., B. Kane, D. Kittredge, H. D. Ryan and B. Butler. 2011. Measuring urban forestry performance and demographic associations in  Massachusetts, USA. Urban Forestry & Urban Greening. Vol. 10, #2: 113-118.

Kane, B. and  H. D. Ryan. 2009. Residual Strength of Carabiners Used by Tree Climbers. Arboriculture & Urban Forestry 35: 75-79.

Rooney, C., H. Ryan, D. Bloniarz and B. Kane. 2005. The Reliability of a Windshield Survey to Locate Hazards in Roadside Trees. J. Arboric. 31: 89-94.

Kane, B. & H.D. Ryan. 2008. “How Strong Is That Branch You’ve Tied-in To”. ISA ARBORIST -NEWS 17 (6): 50 – 51.

Ryan, H. D., 2007. “To Cable or Not to Cable”. TREE CARE INDUSTRY 18 (7) 32-38.

Ryan, H. D., D. & B. Kane. 2006. “Z-133 Standard Revisions 2006, Safety Standards for Chain-Saw Use, Climbing, Pruning, Rigging, and Removal” ISA ARBORIST-NEWS 15(5): 48-50.