Marielle Drennan is the owner of Champion Tree & Plant Health Care, a full-service plant health care company based out of King of Prussia, Pennsylvania and servicing the Main Line and surrounding areas. Marielle is an ISA Certified Arborist® and a Pennsylvania Department of Agriculture Certified Pesticide Technician. Prior to forming Champion Tree, Marielle worked on her husband's pruning crew for several years. She is a passionate collector of David Austin and antique roses, as well as a Pennsylvania Big Tree enthusiast. Marielle is a graduate of Washington and Lee University, in Lexington, Virginia where she majored in mass communications and double-minored in studio art and film and visual culture studies.

Ari Miller, RLA, ISA Certified Arborist - Ari Miller is the director of design at Hinge Collective in Philadelphia, Pennsylvania, a public interest design firm that puts community engagement and public participation at the forefront of their practice. As both a landscape architect and arborist, Ari has always advocated for the integration and restoration of natural systems in urban design. Over the course of his 17-year career, Ari has worked as an arborist at Morris Arboretum, as a green roof design specialist at Roofmeadow, and has also led large-scale civic design projects at OLIN Partners. At Hinge, he uses this experience to help communities find design solutions that best support human and ecological health in their own neighborhoods through the enhancement of public space and community-led planning. Some notable projects include the Philly Tree Plan, Resilient Communities Stormwater Initiative, Unity Park, and Frankford Pause Park. Ari has also been adjunct faculty at the Weitzman School of Design at the University of Pennsylvania and Jefferson University.

David Teuschler is the Chief Horticulturist for Devil Mountain Wholesale Nursery. He established the nursery’s propagation program and currently directs the propagation and inventory teams for the company’s sixteen locations across California. David has worked in the nursery industry for three decades, including many years at Valley Crest Tree Company. While there, he served as Plant Health Care Manager for the Specimen Tree Division, Account Manager in the Estate Gardens Division, and, most notably, Chief Arborist for the Apple contract grow, responsible for growing over 7,000 trees – half from seed – for installation at the Apple campus in Cupertino, CA. David is a Certified Arborist and a member of the Western Chapter of the I.S.A. and the I.P.P.S. He is a 3rd generation Californian and has a BS in Ornamental Horticulture from California State University, Fresno.

Nykia Perez Kibler
Nykia Perez Kibler, co-founder of Philly Tree People (501c3), is an ISA Certified Arborist® with a Master in Environmental Studies degree with a focus on Environmental Biology from the University of Pennsylvania (Penn). She also has a Master in Liberal Arts from Penn, a Certificate in Landscape Plants from Temple University, a Master of Library & Information Science from The University at Buffalo, and a Bachelor of Fine Arts in Fine Art Photography from Rochester Institute of Technology. Her two capstones from Penn were: “Philly Tree People: A Case Study on the Formation of a Non-profit Community-based Tree Planting and Tree Care Organization" where she outlined the Pruning Club program and "Management of the Urban Forest: A Zip Code Level Approach" where she outlined the plan for a Green Skills Youth program both of which were heavily modeled after programs after UC (University City) Green in West Philadelphia. She was an intern at Bowman’s Hill Wildflower Preserve where she worked in their native plant nursery, participated in interpretation activities, led guided walks for families, assisted with grounds maintenance, marketing, and data collection. Nykia is generally interested in ecological restoration, urban ecology, urban wildlife, ornithology, wetlands, urban forestry, native plants, biological conservation, road ecology, environmental education, nonprofit leadership, urban orchards, food gardening, green walls, children’s play spaces/gardens, and citizen science. Professionally, she works as a library director and research librarian providing and developing research services for faculty and graduate students at Penn, supporting grants, and disseminating research results via websites and social media. She’s also a girl scout troop leader and engages youth in tree planting, pollinator gardening, camping, and citizen science.

Jacelyn Blank
Jacelyn Blank is an ISA Certified Arborist® with a bachelor’s in fine arts and a master’s in education with Pennsylvania teaching certifications in Elementary and Special Education. She is one of the three co-founders of the federally recognized not-for-profit Pennsylvania Horticultural Society Tree Tender organization, Philly Tree People. When Jacelyn isn’t volunteering her time with Philly Tree People she teaches preschool children part time at a not-for-profit play school in Fishtown called By My Side, where she focuses on child led play and interests, increasing students’ social emotional understandings through incidental teaching opportunities, as well as introducing students to a variety of environmental and art related educational experiences. She also co-founded the Friends of H.A. Brown, her local catchment public school where she completed her student teaching in 2011 and where her son currently attends.
Jacelyn launched her own small business; Blank Slate Trees and Gardens, in 2021 where she works with Philadelphia clients on landscape design, garden creation and maintenance, installation and care for trees and installation of plants for window boxes and planters with an integration of native plants. She is currently completing her Pollinator Steward Certificate through the worldwide organization, Pollinator Partnership. Her ultimate career goals are to combine her love of teaching, arboriculture, and horticulture by continuing Philly Tree People’s Green Corps, a youth employment, education and empowerment group hiring students living and attending school in the Kensington neighborhoods in order to encourage more urban youth to move into the Green Industry while caring for Kensington’s tree canopy and learning through hands-on experiences.