Our Expert Seattle Tree Crew

Team Lead and Owner

Seattle tree expert, certified arborist, and qualified tree risk assessor Kathy HolzerKathy Holzer is an ISA Certified Arborist (PN-0956A) and a TRAQ Qualified Tree Risk Assessor with 27 yrs of experience climbing, pruning, and assessing trees in the Seattle area. Though she rarely gets to work in the field anymore, Kathy was also a five-time PNW chapter climbing champion and the 2004 world champion climber at ISA ITCC in Pittsburgh, PA. She has a BA in philosophy from Bowdoin College in Brunswick, ME, and is currently studying for the ISA’s highest level of certification – BCMA, or Board Certified Master Arborist.

Kathy is an avid reader, studied Aikido for 20 years, and shares a 1928 “fixer” she bought for the big trees on the lot with her lovely partner Levecke.


Office and Operations Manager

Seattle tree expert and certified arborist Levecke MasLevecke Mas is an ISA Certified Arborist (PN-9217A ) who is proud to work at Out on a Limb Tree Co, and support such an awesome crew, and she is not just saying that because she happens to be married to Kathy. She brings over twenty years of experience in office management to the daily operations of the company, loves keeping track of details and talking to people.

When she’s not working in the office, she enjoys walking, hiking, learning new skills, and traveling as much as possible.


Crew Lead

Seattle tree expert, arborist, and crew lead Dylan BergerDylan Berger is an ISA Certified Arborist (RM 8424A0, a TRAQ Qualified Tree Risk Assessor and recent transplant to Seattle from Colorado. He started his career in the tree industry there doing fire mitigation and invasive species removal with the Southwest Conservation Corps in 2015 before transitioning into arboriculture in 2017. Dylan is really excited to join the Out on A Limb team and continue his career and education in the beautiful pacific northwest.

When not climbing or caring for trees he can be found seeking solitude in the mountains or exploring new recipes and restaurants.


Crew Lead

Seattle tree expert, crew lead, and arborist Andrew HaggertyAndrew Haggerty is a TCIA Qualified Crew Leader QCL-0475 and an ISA Certified Tree Worker Climber Specialist. Andrew is so happy to be a part of the OOL crew. He grew up in the Seattle area and has always found a great appreciation for the natural beauty the area has to offer. Andrew is new to the world of tree care and is extremely excited to grow his skills and knowledge. When not at work Andrew can be found exploring local parks and hiking trails or reading a good book.


Team Member

Landon Jackson is an ISA Certified Arborist (PN-9774A) and is originally from Portland, Oregon where he grew up frequenting the green expanses of Forest Park and Oregon forests. After graduating from Western Washington University with a BA in Urban Planning and Sustainable Development, his passion for ecological systems and urban forestry led him to join on as a member of our ground crew. When not at work, he enjoys skateboarding, building bikes, and camping.


Team Member

Keenan Thompson 
Keenan is an ISA Certified Arborist (PN-9870A). Keenan grew up in Olympia, and fell in love with the Pacific Northwest and its trees on family backpacking trips each summer. After graduating from the University of Washington with a BS in Environmental Science and Forestry, this love drew him to the world of arboriculture and to OOL, where he is excited to be working and learning new skills. When not at work, Keenan enjoys exploring Seattle parks, hiking and backpacking, and game nights with friends.


Team Member

Daniel Johns
Daniel Johns is a second generation climbing arborist recently moved to the Seattle area from Grand Rapids, Michigan. Before discovering his passion in the canopy, Daniel pursued his love for at height work building and maintaining wind turbines. Needing a change of pace, the climber took back to his tree climbing roots and began training at Woodland Tree Service in Michigan. In his free time Daniel is discovering, admiring, and studying the incredible landscape the PNW has to offer.


Team Member

Eric Brown
Eric an ISA Certified Arborist (TX-4182A). Eric was raised in Austin, Texas. Eric started in the tree industry stump grinding and fertilizing in the Texas heat. He quickly moved to Boulder, Colorado to climb bigger and bigger trees. Eric is most recently a transplant from Eugene, Oregon. On the weekends he enjoys hiking and generally being outside with his partner Kate.


Team Members

Harley and Pico
They don’t have logo wear (yet…), but Harley and Pico never miss a morning job briefing