Staff & Board


Cristina Bowerman

Executive Director

Cristina has worked in the nonprofit sector for the past 25 years. She spent 15 years with 501(c)(3) charitable organizations and 10 years with 501(c)(6) trade associations. A native Floridian, she attended the University of Central Florida, where she earned her master's in Nonprofit Management and bachelor's in Advertising and Public Relations. She is a Certified Association Executive with the American Society of Association Executives.

She recently relocated to Tigard, OR with her husband and fur babies. A tree enthusiast, she loves being outside to hike and just spend quiet time in nature. She is excited to be joining Team PNW-ISA and looks forward to learning more about the amazing trees that inhabit the Pacific Northwest region.

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Melissa Amrhein

Education Program Manager

Melissa Amrhein

Melissa has an undergraduate degree in Community, Environment, and Planning and graduate degrees in Forest Resources and Public Administration from the University of Washington. When she is not working on the Continuing Education Program, Melissa enjoys spending time with her husband and daughter, doing yoga, and exploring the great outdoors of the Pacific Northwest.

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Margo Thorp

Education Program Coordinator

Margo graduated from Western Washington University with a Bachelor of Arts in Education, focusing on science education in the K-8 classroom. She has worked as a Coordinator for the UW – Friday Harbor Labs Science Outreach Program and as a Program Coordinator with the University of Washington managing operations for degrees, certificates, and courses focused on the environment, engineering, and technology.

For the past four years, Margo has participated in Horticulture courses at Edmonds Community College with a general focus on arboriculture, pruning, and tree care. She is currently spending a year working as an intern with the Elisabeth C. Miller Botanical Garden in the Seattle area. Outside of work Margo enjoys skate skiing, hiking, boating, gardening, and baking.

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Sharon Korte

Member Services Coordinator

Image of Sharon Korte, a white woman with blond, shoulder-length hair, wearing a black sleeveless shirt. She is standing in front of some tall flowers and a white fence.

Sharon Korte joined the  Pacific Northwest chapter as the Member Services Coordinator in June 2019. Sharon has 7+ years of experience with the international Society of Arboriculture and held roles such as Credentialing Manager and Customer Relations Manager. She has a solid foundational knowledge of membership, credentialing, and arboriculture programming.
Sharon is an avid gardener with a love for flowers. She is a self-proclaimed book-a-holic - reading upwards of 50+ books per year.

Sharon lives in Tuscola, IL with her husband Chris and their two American Eskimo dogs, Crystal and Roxxie.

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Board of Directors

Philip Bennett


Urban Forester, City of Snoqualmie; City Arborist, City of Clyde Hill, in Snoqualmie, WA

Phil is a graduate of the University of Wales, Aberystwyth with a BA in English literature, and is an ISA Certified Arborist, Municipal Specialist, qualified tree risk assessor and former environmental educator. Phil is actively engaged in the disciplines of arboriculture: Planting,mulching, pruning, treating diseases, climbing, and removing trees. Phil is convinced that not only is this the best job in the world, it’s also making the world a better place. Read More About Philip Bennett

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Charles Ray

President Elect

Urban Forester with the City of Vancouver, in Vancouver, WA

Charles Ray is the Urban Forester with the City of Vancouver, Washington. Charles is a graduate from the Ohio State University with a Bachelor of Science in Natural Resources. He is certified through the International Society of Arboriculture as an Arborist and Municipal Specialist. He has worked in both the municipal and commercial arboriculture fields before starting with the City of Vancouver in 2001.

As President Elect, Charles is dedicated to supporting the President and working with the Board of Directors, staff and membership to further the chapter’s mission. Prior to becoming President Elect, Charles served as the PNW-ISA Governance Director.

When not at work Charles spends time with his family, relaxing, laughing, practicing the art of Wing Chun and enjoys good music and coffee.

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Ian Scott


Davey Resource Group, in Shoreline, WA

Ian Scott, a white man with dark hair, a salt-and-pepper beard and glasses.

Ian Scott is a Regional Manager and urban forestry specialist based out of Shoreline, Washington. He has served clients as part of the Davey Resource Group team throughout the Western U.S. and Canada since 1998. He works with many cities to develop urban forest management consulting solutions, deliver urban tree inventories, and provide urban tree canopy assessments.  Ian has a Bachelor of Science degree in Forestry and Environmental Management from the University of New Brunswick, Canada. He is an ISA Board Certified Master Arborist with a Tree Risk Assessment Qualification. He is a 2009 graduate of the Municipal Forestry Institute.

Outside of work, Ian spends time with his family exploring the Puget Sound, volunteering in his community, and supporting local art initiatives.

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Kris Josey


ArborCare Resources, Inc., in Hailey, ID

Kris Josey graduated from University of Colorado, Boulder with a BS in Accounting in May 1989. Upon graduation she worked as a staff accountant with Coopers & Lybrand’s Denver, Colorado office from June 1989 to November 1992. She obtained her CPA license in 1992. Later that year, she moved to Idaho and worked in a local accounting office until June 1996 when she left public practice to be a stay at home mom with her 2 young sons. In early 1997, she and her husband, Bill, combined her business/accounting knowledge with his tree care knowledge to start their family business ArborCare Resources, Inc.  Kris continues to be actively involved with the management of the business.

In 2003 Kris was appointed to the ISA’s finance committee and in 2014 she joined ISA’s conference and events committee. Her goal as the Treasurer for the PNW Chapter is to provide a business perspective to the Board as it explores new initiatives and continues to grow membership services for all members.

In her free time she is a regular at the local CrossFit gym or outside enjoying the Sun Valley area skiing/snowboarding, hiking, or mountain biking.

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Anna Heckman

Member Services

Anna’s education in forest ecology, and urban horticulture led her to a career in natural area management and arboriculture.  Her career has grown her passion for understanding research and bridging the communication gaps between science and management.  Anna has over 15 years of service in government employment ranging from a backcountry field technician to a plant ecologist, vegetation manager to an urban forester.  Anna recently found a great fit applying her skill set as a consulting arborist with Urban Forestry Services Inc.

When not watching baseball, fishing, or listening to great music with her family, you can find Anna trekking through the mountains with her dog, biking through town, playing in the snow or volunteering with habitat restoration organizations.

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Kurt Fickeisen


Symbiosis Tree Care LLC, in Seattle, Washington

Kurt is the owner of Symbiosis Tree Care in Seattle Washington and has worked in arboriculture since 1989. While most work takes place in the greater Seattle area, Kurt spent three years working for a tree service in Boulder Colorado.

Work in these areas has expanded his knowledge of how tree growth patterns can vary from region to region. The primary focus of work is as a Consulting Arborist.

Prior to work in arboriculture, Kurt graduated from the University of Idaho.

In his free time Kurt likes to hike, climb and backcountry ski. In addition, mountaineering from Alaska to California has been part of his life since a young age.

Gregg Staniforth

Continuing Education Director

City of Victoria, in Victoria, BC

Since 1999, Gregg has committed his career to the management and preservation of urban trees in the provinces of Quebec and British Columbia.

He completed a Bachelor’s degree in Forest Science from the University of
British Columbia followed by a Master’s of Science in Arboriculture and
Urban Forestry from the University of Central Lancashire. Gregg is ISA Certified and Tree Risk Assessment Qualified.

As a Board Member of the Quebec Chapter of the ISA (SIAQ) for 6 years, Gregg directed a group of industry professionals for the translation and localisation of the ISA Certification Program into Canadian French. He later became the Chapter’s first Certification Liaison and Exam Protector. Gregg is a recipient of the SIAQ’s Alphonse-Guimont award for excellent achievement in the professional practice of arboriculture and an ISA True Professional Award for his contribution to industry.

Gregg is an avid communicator who is driven to share knowledge, experience and resources with industry practitioners. His approach is centred on fostering inquisitiveness, keen observation, discussion and a deeper understanding of the issue at hand. Through these values, Gregg helps and engages people to equip themselves to better understand and manage their urban forests.

He is committed to succession planning in the industry so the next generation of urban foresters and arborists is even better equipped than ours. Continuing education and educational opportunities are a critical part that. Gregg cares about the future of urban forestry and the dedicated people who make that future possible. For Gregg, working in urban forestry and arboriculture is more than a passion - it’s a way of life.

Jon Pywell

Public Outreach Director

Urban Forester, City of Corvallis Parks & Recreation, in Corvallis, OR

Jon Pywell is a graduate of the University of Florida with a degree in Natural Resources. He is a Board Certified Master Arborist and Municipal Specialist and is TRAQ certified. As the Urban Forster for the City of Corvallis, Oregon he maintains an inventory of approximately 15,000 street trees and oversees restoration projects in over 1,200 acres of natural areas. This diverse urban forest presents new challenges daily and gives Jon a constant source of inspiration and questions about arboriculture, trees and the people who live among them.

As the incoming Public Outreach Director, Jon is excited to work with the Board of Directors, Staff and Membership at PNW-ISA to increase the visibility and connectedness of our ISA chapter through partnerships with our colleagues in allied professional organizations, greater outreach to the public beyond and serving the membership through improved sharing of the latest in science and When not at work Jon spends time with his wife and his four legged children hiking, mountain biking and exploring the world around them.

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Mike Oxendine

Governance Director

Ashland Parks and Recreation Commission, in Talent, Oregon

Mike has called Oregon home since 1985 and lives in the small community of Talent. He is an ISA certified Arborist (PN 7681A), licensed Oregon Landscape Construction Professional (OLCB #15598), and holds an Associates in Science degree, working towards a Bachelors in Innovation and Leadership, and plans to attain a Masters in Urban Forestry.

He loves to serve others, and works full time as the Parks Superintendent for the Ashland Parks and Recreation Commission.  He serves not for profits in his current board positions on the Post Growth Institute Board of Directors, Oregon Community Trees Board of Directors, and PNW ISA Board of Directors.

Mike has worked in the horticulture and arboriculture industry since 2001 and has received numerous awards and certificates for his leadership including the Swampy Award, the Lavender Outstanding Professional Staff Member Award, ALLY Team Award, Pollinator Hero, Raider Recreation Professional Service Award, and the Raider Athletics Appreciation Award to name a few.

Mike is passionate about social justice, social equality, innovation, and leadership. He is an avid environmentalist, outdoor enthusiast, and loves backpacking with his wife Erin and their dog Indy.

“I am very excited to be the acting Governance Director for PNW ISA where I can draw on my education and experience gained from working with many not for profits to help hold PNW ISA to the highest ethical standards, best practices, and our adopted bylaws.”

John Hushagen

ISA Council of Representatives

John has been an arborist since 1980 and a member of the ISA since 1984.  In 1987 he completed his Masters’ of Science in Urban Horticulture and co-founded Seattle Tree Preservation, Inc. He owned and operated this tree care company until its sale to Bartlett Tree Experts and his retirement in February 2018. He has been a certified arborist since 1992, and currently works part-time as a consulting arborist in the Seattle area.  He was elected to the PNW ISA Board in 1988 and served as vice president, president, and ISA representative until 1994.  After hiring the first paid chapter administrator in the early 90’s, and promoting the newly-minted Certified Arborist program, the growth of the PNW Chapter was phenomenal.

In over 30 years of running a tree care company, his greatest challenge was finding enough young men and women who wanted to work for a progressive and innovative company and make arboriculture their career.  John would like to work with the whole ISA to develop strategies for increasing the visibility of our industry, and recruiting a larger slice of the young work force that may or may not be college bound.

John lives in Shoreline, Washington, with Jan, his wife of nearly 38 years.  Together they tend a huge garden and enjoy traveling to S. California often to visit their granddaughters.  John sings in two choirs in Seattle and has been on three European choir tours in the last six years.  He has been known to turn well-known tunes into tree themed parodies.

Evan Sussman

TREE Fund Liaison

Sonshine Tree Care, in Stanwood, WA

Evan Sussman is the owner of Sonshine Tree Care in Stanwood, WA. Evan’s career in arboriculture began in the tropical climate of Hawai'i. In 2012 Evan moved to the Pacific Northwest.

Evan is an ISA Certified Arborist (WE-9274A), and ISA Qualified Tree Risk Assessor. He is actively involved in the furthering of the arboriculture profession in our chapter through community engagement, as a professional tree worker instructor, and in the development of apprenticeship programs.

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