International Society of Arboriculture

10/08/2026

The latest issue of Tree-sources is out now!

The 2026 International Tree Climbing Championship (ITCC) Rule Book is now available in print through the ISA Store. The 2026 ITCC Rule Book supports arborists competing in five preliminary events and a Masters’ Challenge, emphasizing safety and alignment with current best practices.

For more information visit: https://mailchi.mp/fbca0ec21afc/tree-sources-10-8-26

10/07/2026

ISA is proud to recognize Carlos Llanos-Rojas as the recipient of the 2026 Millard F. Blair Award for Exceptional Contribution to Practical Arboriculture: https://youtu.be/24szuy7dKzE?si=D6t142Wbqp50wceK

The Millard F. Blair Award recognizes individuals whose service has substantially contributed to practical arboriculture.

Llanos-Rojas is a Colombian forestry engineer with extensive experience in arboriculture since 1996. He became an ISA Certified Arborist® in 2003 and a Certified Tree Climber in 2018. As the CEO of ASFOR Group, founded in 2003, he has significantly contributed to the field. He co-founded the Colombian Arboriculture Association and the Latin American Institute of Arboriculture, fostering a professional community focused on tree care and urban forest management.

Holding a master’s in development and environment from the National University of Colombia and a master’s in arboriculture from the Complutense University of Madrid, he is currently pursuing a Ph.D. in environmental and sustainable engineering at Francisco José de Caldas District University. Additionally, he previously served on the ISA Board.

To view the full list of ISA 2026 Award Winners, visit https://www.isa-arbor.com/Membership/Member-Recognition/Awards-of-Distinction

10/05/2026

Registration is open for the ISA 2026 Virtual Event! Join us for on-demand education at your own pace starting 16 November through 2 December. ISA Members receive a discount on registration so now is a great time to become a member and save on this educational experience!

To learn more about membership visit: https://ow.ly/YHEG50ZUwh4

To learn more about Virtual Event and register, visit
https://ow.ly/hhoP50ZUvfB

Access on-demand educational content featuring industry leaders from around the globe, sharing insights about research, practice, and technology

10/02/2026

ISA members, the October issue of Arborist News is here!

This month’s issue takes a look at "The Beginning of the International Tree Climbing Championship", "The London Planes of Wi******er College", "More than Just New Questions: How the ISA Certified Arborist Utility Specialist® Exam Evolves with the Profession", and more.

Explore the October issue at: https://ow.ly/tUbq50ZTVT7

09/30/2026

The September issue of Climbers’ Edge is out now! The 50th ITCC is almost here!

Hear from John Ball as he recalls the beginning of the International Tree Climbing Championship. Plus learn more about how you can volunteer for the Latin American Tree Climbing Championship!

To read the full issue, visit https://ow.ly/MyUW50ZTcJY

09/29/2026

ISA is proud to recognize Lara Roman, Ph.D., as the recipient of the 2026 L.C. Chadwick Award for Arboricultural Research. https://ow.ly/6xsW50ZSlgk

The L.C. Chadwick Award for Arboricultural Research recognizes individuals whose research has contributed valuable information to arboriculture.

Roman is a research ecologist with the USDA Forest Service, focusing on tree mortality, growth, canopy cover change, and urban tree planting factors. She has led or coauthored over 80 publications, including a significant urban tree monitoring field guide, and received funding from organizations like the TREE Fund and the USDA.

Roman has served on the ISA's Science and Research Committee and as a guest editor for Arboriculture & Urban Forestry, while also reviewing for various academic journals. She holds a bachelor's and a master's in biology and environmental biology from the University of Pennsylvania, and a Ph.D. in environmental science, policy, and management from UC Berkeley.

To view the full list of ISA 2026 Award Winners, visit https://ow.ly/He7p50ZSlgj

09/24/2026

The latest issue of Tree-sources is out now!

The 2026 International Tree Climbing Championship (ITCC) Digital Rule Book is available through the ITCC website. This edition contains the official rules for all ISA Tree Climbing Championship events, effective 1 October 2026.

To download the 2026 ITCC Digital Rule Book visit: https://ow.ly/V4cB50ZQ6Ny

For more information visit: https://ow.ly/UY0z50ZQ6Nv

09/22/2026

ISA is proud to recognize Joe Aiken as the recipient of the 2026 Sharon J. Lilly Award of Achievement. https://ow.ly/gOM550ZQe7S

The Sharon J. Lilly Award of Achievement is in recognition of sustained outstanding efforts or contribution to the advancement of ISA.

Aiken has been an ISA member for over 20 years and has held various roles within the organization, including serving on the ISA Centennial Committee, being a keynote speaker at the ISA 2024 International Annual Conference, and being the Committee Chair for the ISA 2026 International Annual Conference. He traveled to ISA chapters to educate members about arboriculture's history.

Outside of ISA, Aiken is a founding member of the Arboriculture Society of Michigan Foundation and curates the Arboriculture Historical Society. He also co-hosts the Discovering Forestry Podcast, interviewing fellow ISA Certified Arborists®. Professionally, Aiken has spent more than two decades at Arborjet, where he supports research and collaborates with universities on tree injection technologies to combat invasive pests and threats to urban forests.

To view the full list of ISA 2026 Award Winners, visit https://ow.ly/ZP0g50ZQe7R

09/21/2026

The International Society of Arboriculture (ISA) and the Korean Arborist Association (KAA) are pleased to announce the signing of a Memorandum of Understanding (MOU), formally recognizing KAA as an ISA Associate Organization.

This agreement strengthens collaboration between arboricultural professionals in Korea and the global ISA community, creating new opportunities to share knowledge, advance professional standards, and support the growth of the arboriculture profession.

The MOU was signed by Byung-mo Kim, President of the Korean Arborist Association, and Samuel Ma, ISA Board President.

We look forward to working together to advance arboriculture and build stronger connections among tree care professionals around the world.

Welcome, Korean Arborist Association, as an ISA Associate Organization!

09/18/2026

ISA is proud to recognize Greg Dahle, Ph.D., as the recipient of the 2026 Alex L. Shigo Award for Excellence in Arboricultural Education. https://ow.ly/yECu50ZOJNv

The Alex L. Shigo Award for Excellence in Arboricultural Education recognizes the important role education plays in enhancing the quality and professionalism of the arboriculture industry.

Dahle is a professor of urban forestry at West Virginia University, teaching courses in arboriculture, urban forestry, and sustainable living. He also delivers guest lectures at West Virginia University and Allegheny College of Maryland and has lectured at Purdue University and Rutgers University. Dahle instructs high-achieving high school students at the West Virginia Governor’s Honors Academy on sustainable urban forests.

Additionally, he is an ISA TRAQ instructor and teaches for the ISA Mid Atlantic Chapter's arborist certification preparation program. He has served as the program coordinator for the Forest Resources Management program at WVU and held leadership roles, including past president of AREA and current vice president of the Mid Atlantic Chapter of the ISA. Dahle is an ISA Board Certified Master Arborist® and ISA Tree Risk Assessment Qualified.

To view the full list of ISA 2026 Award Winners, visit https://ow.ly/wCre50ZOJNx