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certified arborist
ISA Certified Arborist Logo
ISA Membership Logo

Certified Arborist


International Society Of Arboriculture

Any person with a pickup truck and a chain saw can call themselves an arborist but not just anyone can say they are an ISA (International Society Of Arboriculture) Certified Arborist. An arborist is anyone who works in the tree service industry; however they are not required to have any education, pass an exam or prove their knowledge of tree care in any way.


ISA Certified Arborists are individuals who have achieved a high skill level of knowledge in the art and science of tree care with a minimum of three years of experience in the industry and have passed a comprehensive examination put together by the International Society of Arboriculture. They are also required to continue their education in order to maintain their certification, ensuring their knowledge is updated on the latest arboriculture techniques. The ISA Arborist Certification is a non-governmental voluntary process that operates without mandate of law. It is an internal self-regulating device administered by the International Society of Arboriculture, and therefore, cannot guarantee or assure the quality of performance. Certification provides a measurable assessment of an individual's knowledge and competence required to provide proper tree care.

Our Estimators

Gary Allen, ISA Certified Arborist - Allen's Tree Service Inc.

Gary started working in the tree industry in 1973 as a tree climber before he created Allen’s Tree Service Inc. He educated himself, his employees, along with his clients and obtained his certification from the ISA on May 1, 2002. Gary served as the Vice President of the St. Louis Arborists Association 2005 & 2006 and President in 2007 & 2008. Gary is proud to pass his knowledge and learned techniques onto his employees to ensure employee safety and customer satisfaction.

Gary Allen MW-4276A

Jeff Allen, Isa Certified Arborist - Allen's Tree Service Inc.

Jeff started working for Allen’s Tree Service Inc. in 1980 as a groundsman and pursued his career as a tree climber. After several years of experience and training, Jeff became Project Coordinator and estimator for our tree crews. Jeff obtained his ISA certification on April 10, 2008 and is continually educating our employees.

Jeff Allen MW-4818A

Kevin Gallagher, ISA Certified Arborist - Allen's Tree Service Inc.

Kevin began working in the tree and landscape industry in 1984. He obtained his ISA certification in 2001. Kevin specializes in diagnosing plant disorders and has a broad range of knowledge in landscaping and lawn care. Kevin served as the Vice President of the St. Louis Arborist Association in 2009 and President in 2010 & 2011. He currently serves on the Board of Directors of the St. Louis Arborist Association.

Kevin Gallagher MW-4189A

John Beckman, ISA Certified Arborists - Allen's Tree Service Inc.

John Beckman MW-0342A

John graduated from the University of Missouri-Columbia in 1982 with a Bachelor’s of Science in Forestry and began working in the industry in 1983. John obtained his ISA certification in 1995 then attended the Davey Institute of Tree Science in 1999. In 2006 John became Certified Tree Care Safety Professional through the Tree Care Industry Association to increase knowledge of safety and training of employees. In 2014 John was credentialed as Tree Risk Assessment Qualified to perform structural tree assessments. John specializes in plant disorders, remedies, the evaluation of trees, Tree Risk Assessments, safety training as well as estimating tree maintenance costs. John served as Vice President of the St. Louis Arborist Association in 2014/2015, President in 2017/2018 and is currently on the board of directors for the St. Louis Arborist Association. 

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