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Mark Fallon, Director

Mark came to Briar Bush in January 2003 and became Director in 2020. He holds a BA in Zoology and French from Connecticut College. From the coasts and mountains of New England to the Rockies of Wyoming to the Delaware River, Mark has spent his professional life teaching, coaching and interpreting in the outdoors. Mark leads our talented team in all aspects of operations and projects. For 18 years as Senior Naturalist, Mark answered the public's questions about nature, taught programs, worked with volunteers, and developed a thorough knowledge of native and invasive exotics plants and horticulture. He has managed such projects as the Nature Playscape, Members' Grove and Pond restoration. Originally from Massachusetts, Mark now lives with his family in Mt. Airy, Philadelphia.

Estelle Allen, Program and Guest Services Coordinator


Estelle Allen recently joined the Briar Bush team as the Program and Guest Services Coordinator. Estelle spent 35 years at a major telecommunications company holding positions focusing on customer service and project coordination. Following retirement, she worked with the Abington Township Community Police Division providing support to the Police Athletic League, and later accepted a Customer Service position with AARP. She is committed to providing service to others, most importantly her church, The Abington Youth Aid Panel, and Montgomery County Senior Services.

Estelle lives in Glenside PA where she and her husband raised their 2 children. She cherishes the time she has with their 2 grandchildren. She enjoys family, bowling, traveling, planning, and hosting group activities for family and friends.

Melissa Eldridge, Program and Summer Camp Director

Melissa holds a B.S. in Recreation Management and minors in Biology and Environmental Studies from Lock Haven University of Pennsylvania. Before joining the full-time education staff in 2014, Melissa had worked at Briar Bush for two summers as a Camp Counselor. Now as the Program and Summer Camp Director, Melissa is responsible for developing and updating programs for families, senior adults, Scouts, and individuals with disabilities. She's enjoyed developing the well-received SAGE Sessions program for senior adults and the Family Nature Night program for children with autism spectrum disorder. Melissa also directs the Summer Camp program and leads some camps herself. In 2016, she received the Daisy S. Klinedinst Memorial Award for her continued dedication to expanding her involvement with environmental education in Pennsylvania from the Pennsylvania Association of Environmental Educators. Melissa considers herself a naturally curious person and a life-long learner who enjoys spending time in nature hiking, camping, kayaking, and exploring. She resides in Blue Bell with her husband, Scott.

Katie Fisk, Animal Curator and Educator

Katie has been with Briar Bush since 2009. She received her BS in wildlife biology from Colorado State University and an MS degree in Environmental Education and Interpretation from the University of Wisconsin Stevens Point. Her background consists of work with both people and animals through organizations such as the US Fish & Wildlife Service, Tampa's Lowry Park Zoo, Busch Gardens Tampa Bay, and various bird research groups. At Briar Bush, Katie loves the variety of teaching audiences of all ages and caring for the animal ambassador collection along with an amazing group of dedicated volunteers.  When not working, you might find her hiking, kayaking, or working in her native garden.

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Karen Foster, Development and Event Coordinator

Karen joined the Briar Bush team in 2016 as the weekend educator. She has a B.S. in Ecology and brought with her a combination of experiences in outdoor education, after-school and summer camp programming, curriculum development, and environmental research. Karen began collecting these experiences at Churchville Nature Center leading hikes and Lenape programs followed by time in the high desert of Las Cruces, New Mexico as part of the USDA’s environmental research program. Since then, Karen has worked with the Fairmount Park Commission, at the Schuylkill Center for Environmental Education, and on a research team at Philly U. Karen enjoys working with Briar Bush's friendly and knowledgeable staff, and has loved being a part of her local nature center, as she believes that the key to creating a healthy environment begins in your own backyard.

Ehren Gross, Senior Naturalist

An experienced educator, Ehren has been in the field of Environmental Education since 2002. Before Briar Bush, he worked in various National Parks as a Park Ranger giving talks, leading guided hikes and developing Enviro Education programs for the public. He is most comfortable in front of an audience performing live animal shows or in-classroom demonstrations. Ehren has his Bachelor's degree in Environmental Science from West Virginia Wesleyan College and a Masters in Environmental Education from Arcadia University. In his free time he loves reading nature stories, astronomy, and bush crafting. Ehren lives in Abington with his wife, daughters, chickens and colony of bees.

Heidi Malizia, Environmental Educator

Heidi holds a degree in Elementary Education with a concentration in environmental science from Penn State University. Prior to Briar Bush, Heidi taught 3rd grade for two years in a formal education setting. She loved teaching, but missed the outdoors.  After completing an internship at Shaver’s Creek Environmental Center, she was hired as the Outreach Coordinator at Great Valley Nature Center where she lead programs for all ages, and developed the Head Start into Nature Program. In addition, she ran their annual auction, taught summer camp and outdoor school programs, facilitated team building exercises, ran teacher workshops, and lead adventure trips to kayaking, camping and hiking destinations. Heidi began her journey at Briar Bush in 2009 as a part-time weekend educator, but she can be found on the property leading the Magic Mornings and Nature Pioneer preschool programs. She also travels to all 25 Montgomery County Head Starts and 14 Pre-K Counts programs twice a year, and leads adventure summer camps. Most recently, Heidi became part of the Feather Our Nest Auction and Gala development team. In her spare time, Heidi loves to be outdoors kayaking, hiking and going on adventures with her husband, three daughters and her dog.

Kyrstin Schwarz, Part-Time Educator

Kyrstin has a Bachelor’s Degree in Conservation and Wildlife Management with a minor in Education. While in college and since graduating, Kyrstin has worked as a tutor, a pet groomer, a camp counselor, and a substitute teacher. Kyrstin has also worked with different animals from cats to cows to giraffes. She loves spending time outside with family and friends, camping, traveling the world, and wildlife photography. When she’s not outside, Kyrstin spends her time reading, painting, and playing games. She grew up in New Jersey and moved to Pennsylvania in 2017. Kyrstin now lives in Doylestown with her fiance, Jeff, and her calico cat, Cheyenne.

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Bryna Steele, Part-Time Educator

Bryna Steele, Environmental Educator Bryna has an undergraduate degree in Landscape Architecture awarded by the University of Edinburgh and an MSc in Biodiversity and Plant Taxonomy awarded by the University of Edinburgh and the Royal Botanic Gardens Edinburgh. During her undergraduate degree, Bryna worked at the Royal Botanic Gardens Edinburgh in the Glasshouses with both display and research collections specifically in the temperate glasshouses, Begonia collection, and quarantine glasshouse. In her MSc, her dissertation was researching conservation translocation methods in lichens. Professionally, she has worked in horticulture at a variety of gardens, both in the US and in the UK. In addition to being a part time educator at Briar Bush, Bryna works as an Estate Guide at Winterthur. In her free time she enjoys spending time with family and friends, going on walks, reading, engaging with art, and thrifting. Bryna currently lives in Philadelphia.

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