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2013 ISA True Professionals of Arboriculture



Terrill Collier

Terrill Collier

Terrill Collier is the second-generation owner of Collier Arbor Care in Clackamas, Oregon. He carries on the deeply-rooted traditions started by his father while building the business to become one of the premier tree care companies in Oregon. Collier’s leadership and commitment to the industry are just some of his traits that personify an ISA True Professional of Arboriculture.

Collier promotes proper tree care to the public, employs a full staff of ISA Certified Arborists, and generously donates his time to tree causes. He and his family have raised thousands of dollars for tree research by bike riding in the TREE Fund's annual STIHL Tour des Trees.

Collier is admired for carrying out his daily activities with a positive attitude and selflessly sharing his knowledge with others. He is also the 2013 recipient of the Honorary Life Membership, an ISA Award of Distinction.


Richard Herfurth

Richard Herfurth

Richard Herfurth of Lyndeborough, New Hampshire, is known for his selfless approach in the personal time he gives to support industry and community events. An ISA Board Certified Master Arborist and safety and training coordinator for Bartlett Tree Experts-New England Division, Herfurth teaches all aspects of safety and arboriculture to every employee, whether in management or production.

Herfurth also oversees the Bartlett Internship Program in the New England region with the goal of providing students with strong experience in as many field skills as possible. With a professional manner and thoughtful style, he has also worked with thousands of tree care consumers in the U.S. and Canada.

Richard Herfurth is a mentor, a teacher, and a dedicated promoter of arboriculture — all examples of what ISA True Professionals stand for.


Scott Liudahl

Scott Liudahl

Scott Liudahl, the city forester for Fargo, North Dakota, collaborates with many individuals and organizations to help achieve his goal of benefitting the entire community with a safe, healthy, and diverse urban forest.

His community involvement also includes working with at-risk teenagers to teach them proper tree care, helping to create living snow fences using trees to protect a neighborhood during harsh winters, and developing a pre-mitigation program to minimize the local impact of the emerald ash borer.

Liudahl promotes the ISA Certification program by requiring full-time Forestry Department field staff to become ISA Certified Arborists within the first year on the job. Today, one-third of his workers have been inspired to achieve additional credentials.

Scott Liudahl brings out the best in others and in himself — a leader and an ISA True Professional of Arboriculture.


Jim McCready

Jim McCready

To Jim McCready, being recognized as an ISA True Professional of Arboriculture means being respected by your peers and the groups you belong to for moving the profession forward.

McCready is the owner of McCready Tree and Forestry Consulting in Carlton Place, Ontario. Because his city does not have funds to hire staff to properly care for urban trees, McCready volunteers as the town arborist, offering his expertise in forestry and arboriculture as a contribution to his community.

Even in retirement, McCready has increased his activity to encourage the use of proper tree care practices for growing healthy trees across Eastern Ontario, from tree planting projects with Tree Canada to the development of the Regional Forest Health Network. As a True Professional, Jim McCready values ISA’s promotion of best practices for urban trees and urban forestry across the landscape.


Edward Milhous

Edward Milhous

Ed Milhous is a teacher who freely gives his time to support developing arborists in their careers. As the owner of his consulting firm, TreesPlease, in Haymarket, Virginia, Milhous also has earned an outstanding reputation among both consumers and other arborists for his skill in resolving tree problems.

Milhous is a founding member of the ISA Mid-Atlantic Chapter, and was also instrumental in launching the ISA Certified Arborist program at the local level. He was also one of the first arborists to become TRACE-qualified in his region. For the past 25 years, he has promoted arboriculture at the Virginia Tech Spring Camp as a way to educate others and give back to the industry.

Ed Milhous’ commitment to education and outreach are the qualities that make him an ISA True Professional of Arboriculture.