Scott D. Baker, RCA

Principal Emeritus

In April 2024, after 25 years of dedication to Tree Solutions, Scott stepped away from day-to-day operations. During his tenure with TSI, he mentored dozens of arborists and brought passion and enthusiasm to our office and our industry. While he no longer takes on clients, he still consults on projects with us and supports our training program.

His consulting experience spanned advanced testing and tree diagnostics, treehouses and zip line installation, and tree protection. In 2018 he was awarded the International Society of Arboriculture Honorary Life Member award for his contributions to the industry.

His extensive knowledge of tree biology has helped him become renowned as a speaker and educator internationally, teaching about tree diagnostics, tree-supported structures, and tree risk assessment (ISA Tree Risk Assessment Qualification).

He now has more time to spend celebrating the outdoors as he volunteers with the Ancient Forest Society and the Tour des Trees – a 500+ mile annual bike ride to raise money for the TREE Fund (Tree Research and Education Endowment Fund).

And he LOVES his new identity as a Grandfather.

Sean Dugan, RCA

Principal

Sean is a senior arborist and urban forester with over 25 years’ experience assessing and managing trees, and people’s interactions with them. He is an expert diagnostician and investigator, and a leader of the Tree Solutions Inc. team. His specialties include construction management of tree retention plans, municipal permit review and code development, integrated pest management (IPM), advanced testing and analytics of tree structure and stability. He is an accomplished expert witness and has testified in cases including SEPA and MUP hearings, land use disputes, timber trespass, fire damage, and landscape appraisals. From housing developments to native plant restoration, his projects have seen it all.

Sean is passionate about being a father to his two girls. Other possible Sean sightings: sitting on the porch with his lovely wife, traveling to sport events, enjoying good food, and beach combing. Go Hawks!

Holly Iosso, RCA

Principal

Holly is a senior arborist and urban forester with almost twenty years’ experience at Tree Solutions Inc. She has been instrumental in business growth, leadership development and internal management, while refining her technical expertise. Her specialties include tree retention planning, critical area restoration, appraisals and municipal tree regulation and enforcement. Her projects have included public parks and trails, housing development, residences, and campuses.

Holly actively gardens and loves plants of all sizes. She spends her free time digging in the dirt with her two children, playing the guitar, and binge-watching Masterpiece Theater.

Haley (Galbraith) Sonerholm 

Arborist Manager

Haley is a senior arborist with over ten years of consulting experience with Tree Solutions Inc., and as of June 2022, serves as manager for our arborist and operations staff. With a broad skill set in both the office and the field, she ensures that our team consistently provides the expertise and quality work product that has set us apart from others. She has performed advanced assessment of trees from top to bottom throughout western Washington and further afield, ranging from urban-residential properties to remote forest ecosystems. Her specialties include tree risk assessment, management planning, evaluation of trees as support structures (ziplines and treehouses), municipal tree ordinances and code enforcement

Her leadership skills have been refined over the years; she has served on the Board of Directors for the Pacific Northwest Chapter of ISA and the Washington Community Forestry Council for DNR. Haley and her husband reside on the spectacular Key Peninsula where they are establishing a permaculture farm and food forest.

Katherine Taylor 

Senior Arborist

Katherine is a senior arborist with over 12 years of experience in arboriculture, horticulture, and environmental consulting. She joined our team in 2015 and her passion for urban forestry and education shines through every project she is on. Katherine leads tree retention and protection efforts on large development projects seamlessly working with project teams from the design phase through the construction phase. She also specializes in visual tree assessment, advanced testing, and risk analysis. As a skilled climber, she conducts aerial canopy inspections and enjoys working on zipline and canopy tour projects. She is an experienced speaker and has presented to various groups on tree biology, sustainable landscape management, integrated pest management, tree protection during development, tree supported structures, and others.

Out of the office, Katherine can be found volunteering with the Women’s Tree Climbing Workshop, or maintaining her collection of 100+ indoor plants!

Tyler Bunton

Senior Arborist

Tyler manages all GIS mapping for Tree Solutions Inc. and leads our advanced testing division with training, research, and experimentation. His skill set also includes tree protection during construction and large inventory projects. His past fieldwork experience has been with the US Forest Service in Montana, the Montana Conservation Corps, and as a lead research assistant at the University of Wisconsin – Eau Claire.

When not working, Tyler enjoys camping, native plant ID, collecting records, and (space-dependent) refurbishing old crosscut saws.

Connor McDermott-Grossman 

Arborist

Connor leads TSI’s climbing arborist group, bringing expertise from his background as a production arborist. From roots to shoots, he is a wholistic tree assessor who conducts aerial assessments, root crown excavations, and advanced decay testing. He is pragmatic with his approach to vegetation management and plant health care and works with each client to provide the right solution for each unique site.  His projects with Tree Solutions have spanned residential diagnostics, integrated pest management, campus vegetation management planning, and tree retention. He made his start in the landscape industry under the tutelage of Cass Turnbull, local legend and founder of Plant Amnesty, where he honed his skills in fine pruning and landscape management. Additional field experience has included production arboriculture and working on restoration crews throughout the Puget Sound region.  

In his free time Connor enjoys backpacking, biking and cooking with good friends. Most proud dish? Chicken cacciatore.

George White

Arborist

George is a passionate arborist with a background in production arboriculture and an education in biology. He draws on his industry experience and botanical knowledge to perform informed tree assessments and provide realistic tree management strategies. He specializes in residential consultations, advanced assessments, and tree protection during construction. Prior to his work at Tree Solutions Inc., George worked as a production arborist, conducted ecological research with the Army Corps of Engineers, and worked as a guide and outdoor educator.

When not being a professional tree-geek, George can be found hiking, climbing or backcountry skiing in the Cascades, or skateboarding at Judkins park.

Charlie Vogelheim

Arborist

Charlie is an arborist and project manager who works on tree retention and construction sites, as well as critical slopes and native growth protection areas. His experience includes restoration and stewardship of forests and wetlands. He is passionate about community forestry, which includes nurturing healthy urban forests, resident engagement, and accessible (and equitable) green spaces.  

Outside of work Charlie enjoys cooking for friends, learning new crafts, seeking out swimming holes, and planning multi-modal treks across the region.

Ted Lyden

Operations Manager

Ted handles all things related to our operations, including arborist scheduling and coordination, and proposals.

A former recruiter for technology companies, Ted brings his charisma and human touch to the TSI team.

Jessi Detert

Project Coordinator

Jessi manages the administrative side for all our construction and development projects, including proposal writing, estimating, scheduling and collaboration. 

Jessi has worked professionally, as well as in a volunteer capacity, for various non-profit organizations for over 30 years. She believes in investing her time in organizations with a good mission! She is a nationally certified ACE Group Exercise Instructor and Cycle Instructor, and always carves out time to get on a bike. She is an avid hiker, traveler, and general outdoor enthusiast. What she enjoys most is sharing those adventures with her husband and two children.

Shannon O’Bent

Business Coordinator

Shannon has been with Tree Solutions Inc. for over 9 years and is proud to have worn many hats for the company on both the administrative side as well as a field arborist. Now part time, she manages accounts receivable, contract review, project management support and chief party planner! 

Outside of the office, Shannon spends time singing with jazz and pop cover bands, with a special fondness for the band she started with her husband PepperJill and Jack. She also enjoys cooking, attacking weeds in the garden, and being mom to the cutest little boy (soon to be boys) ever.

Julia Bacharach

CFO, HR Director

Julia is an integral part of our leadership team and has been “counting the beans” for Tree Solutions Inc. since 2013. Besides numbers, spreadsheets, insurance and employment benefits, the Seattle native swims, hikes and enjoys quality family time.