Board of Trustees

Executive Committee

Heather SaundersPresident
John EwingVice President
Sandra Lutz, CPATreasurer
Tracy Green ClarkSecretary


Rena Barnett
Eric Chapman
David M. Charlton
Linda H. Ciavarelli
James R. Flandreau
Andrew W. Harobin
Don Helwig
Angela Horstmann
Edward Rydesky
Thayer Schroeder
Jessica Strine
Jeffrey Welsh
Dennis Westley

Senior Management

Mandy C. Santiago
Mandy C. SantiagoExecutive Director
610-566-9134, ext. 207

Mandy is an accomplished nonprofit management and fundraising professional, deeply rooted in the Greater Philadelphia nonprofit community. She is a creative, strategic thinker, a good listener, and a nature-lover. A resident of Springfield, Delaware County, Mandy is also a long-time member of the Arboretum.

Mike Karkowski
Mike KarkowskiDirector of Horticulture
610-566-9134, ext. 222

Mike came to Tyler in 2004. He is responsible for the management of the Arboretum’s Horticulture Department, which maintains Tyler’s collections, plant records, natural areas, hiking trails, and historic buildings. Mike earned a Bachelor of Science from Purdue University in Landscape Horticulture and Design. His previous work includes Horticulturist and Director of Physical Plant and Grounds for The American College and Hardscape Consultant for a North Shore firm in the Chicagoland area. Mike enjoys building projects at home and church, building tree houses for his two children, and kayaking with family.

Amy Mawby
Amy MawbyDirector of Public Programs
610-566-9134, ext. 301

Amy came to Tyler in 2013. She is responsible for the management of the Arboretum’s Education Department and oversees the coordination of volunteer services and Visitor Center staff and operations. Amy earned a Bachelor of Science from Cornell University and a Master of Science degree in Public Horticulture from the University of Delaware’s Longwood Graduate Program. She previously worked as Education Coordinator for Bowman’s Hill Wildflower Preserve and has interned at Morris Arboretum, the New York Botanical Garden, and Cornell Plantations. Amy is a bit of a shutterbug and enjoys nature photography.

Mary Beth Jackson
Mary Beth JacksonDirector of Development
610-566-9134, ext. 206

Mary Beth grew up playing outdoors in the farmlands of Tennessee and on the beaches of Florida’s Gulf coast. Many family vacations were adventures in camping, hiking, canoeing, and watching wildlife. Mary Beth earned her Bachelors of Arts in Psychology from Emory University and was thrilled to find Tyler when she moved to Pennsylvania. She sees Tyler as offering the complete package of outdoor experience with tree houses, historic trees, hiking trails, woods, and gardens, all on a Quaker family homestead. Mary Beth has been fundraising for Tyler since 2011, becoming Director of Development in 2015. She’s worked in Development and Alumni Relations at Penn’s School of Nursing and School of Arts and Sciences. She’s also consulted for nonprofits in fundraising and campaign management.


Caitlin AnelloMembership & Annual Giving Manager
610-566-9134, ext. 208
Alison DamePlant Recorder
610-566-9134, ext. 220
Austin DeputyGardener
610-566-9134, ext. 221
Beth HoppeFinance Manager
610-566-9134, ext. 204
Julia Lo EhrhardtCommunity Outreach Manager
610-566-9134, ext. 305
Liz HornbachYouth Programs Manager
610-566-9134, ext. 302
Brian KirkVisitor Center Lead Associate
610-566-9134, ext. 212
Joanne LandauRegistrar
610-566-9134, ext. 303
Nicole O’MalleyDevelopment Administrator
610-566-9134, ext. 209
Kathryn OmbamOffice Manager
610-566-9134, ext. 200
Brian PratoSpecial Events Manager
610-566-9134, ext. 210
Rebecca SilveySchool and Community Programs Coordinator
610-566-9134, ext. 306
Nicole SippleVisitor Center Associate
610-566-9134, ext. 212
Mallory SmythGardener
610-566-9134, ext. 223
Sarah SpauldingVisitor Center Associate
610-566-9134, ext. 212
Bess TroutGardener
610-566-9134, ext. 223
Jules WallsVisitor Center Associate
610-566-9134, ext. 212
Jeff WilsonArboretum Manager
610-566-9134, ext. 219