Holden Staff Instructors

David Burke, PhD, holds a bachelor's degree in environmental science from Rutgers University, a master's degree biology from East Stroudsburg University and a doctorate in biology, with concentration in ecology and evolution, from Rutgers University. Burke is a plant biologist whose research focuses on the interactions between plant roots and soil organisms with a particular emphasis on mycorrhizal ecology. He is the chairman of the Research Department at The Holden Arboretum and has an adjunct position in the Department of Biology at Case Western Reserve University.


Chad Clink, community forester, is a graduate of Kent State University with an associates degree in urban forestry and bachelor's degree in horticulture. He here is master's in natural resources from the University of Idaho. Clink most recently worked as an arborist with the Bartlett Tree Experts Company, focusing on teaching and support responsibilities in arboriculture with emphasis on GPS/GIS, tree inventories, management plans, and tree risk assessment. Prior to this, he was an urban forester with the Davey Resource Group managing urban forestry and ecological restoration projects throughout the eastern United States. His responsibilities at Holden are to help restore the aesthetic, environmental, and economic values of trees and forests to communities in Northeast Ohio.  In addition, he is working to establish Holden as the regional focal point where municipalities, institutions, organizations, and individuals can come for information and ideas that will promote improved tree health care and management practices.


Tere Cole-Lang, lead horticulturist at The Holden Arboretum, graduated from Ohio State University with a bachelor's degree in golf course management and plant pathology and a master's degree in integrated pest management. Cole-Lang is currently working on a masters in primary science education. She began her career in the green industry more than 20 years ago on a golf course, spent two years in the Peace Corp, worked at Longaberger Golf Club gaining Audubon Certification status, was superintendent at Springfield Country Club, managed the plant care department and designed landscapes at Scarff's nursery and, most recently, was groundskeeper for Laurel School.


Toby Davidson, horticulture supervisor for the Display Gardens, earned his associate's degree in forestry from Hocking College. He spent the first eight of his 12 years at Holden caring for the trees in the outer collections. He enjoys pruning trees and designing garden spaces.


Lori Diemer is a professional freelance photographer who's award-winning work has been published and exhibited throughout the region. Recently, her work has been selected for the permanent collection of TriPoint Hospital in Concord, Ohio. She photographs special events and portraits, but her true passion lies in nature and travel imagery.  An active member of the Western Reserve Photographic Society and the North American Nature Photography Association, she is an Artist Member of the Red Dot Project in Cleveland Ohio.Her work can be viewed at www.loridiemer.com


Cynthia Druckenbrod began her career at the Cleveland Botanical Garden in 2000 as the Eleanor Armstrong Smith Glasshouse Manager and was responsible for operations of the glasshouse and the plant and animal collections. In 2007, she was promoted to vice president of horticulture and oversees 10 acres of outdoor gardens in addition to the glasshouse collections. Before joining Cleveland Botanical Garden, Druckenbrod served as the director of the Day Butterfly Center at Callaway Gardens in Atlanta, Georgia. Prior to working at Callaway Gardens, Druckenbrod worked at Cleveland Metroparks Zoo as an entomologist and managed the daily operations of the tropical Butterfly Garden.  Druckenbrod has a bachelor’s degree in biology from Case Western Reserve University and a master's in entomology from Auburn University.  She has authored numerous peer-reviewed papers in the fields of entomology and horticulture and frequently speaks at professional conferences.


Julie Dougherty, the assistant manager of guest relations, is a certified interpretive guide from the National Association for Interpreters. She earned her bachelor's degree from Cleveland State University, her master's degree in sports psychology from West Virginia University and her master's in education administration from Ursuline College. She taught outdoor education at Hiram House Camp for 10 years, physical education at St. Vitus for 12 years and served as principal at St. Louis Elementary for seven years.


Roger Gettig, director of horticulture and conservation. Gettig began his career at Holden in 1988 as a native plant intern before becoming full-time staff as natural areas foreman. He left Holden to attend the University of Wisconsin, where he majored in ecological restoration while earning his Master's degree in landscape architecture. He returned to Holden in 1996 as landscape consultant and then assumed the role of land conservation manager.


Lori Gogolin earned an associate's degree in horticulture from Kent State University in 1998. She is a horticulturist at The Holden Arboretum and is responsible for the Arlene and Arthur S. Holden Jr. Butterfly Garden.


Sharon Graper, manager of formal education, began her relationship with Holden in 1981 as a student at Hawken High School, working on her senior project in the Myrtle S. Holden Wildflower Garden. She came back as an intern in 1984 and as a summer employee teaching children’s classes in 1991. Since 1994, she has managed school and youth programming at Holden. She earned her undergraduate degree in environmental science from the University of Virginia and her master’s degree in science education from the University of Delaware.


Clement W. Hamilton, president and CEO. Hamilton grew up in Wisconsin and Ohio, where he developed his three primary passions for nature, baseball and music. He earned a bachelor's degree in geology at Harvard, and a doctorate in ecology and evolutionary biology at Washington University and the Missouri Botanical Garden. He has conducted botanical research and fieldwork in Thailand, Panama and Chile, as well as the United States. He was assistant and associate professor in the Center for Urban Horticulture at the University of Washington, 1985-99, directing the center from 1992-99; executive director of Rancho Santa Ana Botanic Garden in Claremont, Calif. , 1999-2004; and vice president for arboretum programs and director of research at the Morton Arboretum in Lisle, Ill. , 2004-08. In the spring of 2008, Hamilton became president and CEO of The Holden Arboretum, where he seeks to maximize Holden's contribution toward creating a more livable, diverse and ecologically sustainable world by promoting the planting and conservation of trees and forests.


Ethan Johnson, plant records curator, earned his associate's degree from Paul Smith’s College, N. Y. , in forestry and his bachelor's degree in environmental horticulture from the University of Connecticut. He has been Holden’s plant records curator since 1989. As curator he documents the history, growth, phenology, and condition of cultivated plants in the living collection as well as produces plant accession, labels and collection maps.


Aaron Kash joined The Holden Arboretum staff as horticulturist for the Helen S. Layer Rhododendron garden during the spring of 2014 after working in the private tree care industry in Boise, Idaho. Prior to this, Kash served as the curator and forester of Spring Grove Cemetery and Arboretum in Cincinnati, Ohio, for two years where he was charged with curatorial duties, tree selection and planting protocols, tree health care treatments, procuring woody plant material from around the country and forest management of the undeveloped acres. Before joining Spring Grove, he worked as a procurement forester in central Indiana where he met with forest landowners and offered management expertise. Kash earned his bachelor's degree in forestry in 2007 and his master's in forest in 2009 from the University of Montana in Missoula, Montana.


Stephen Krebs, PhD, started at David G. Leach Research Station in 1992 and has been the director of the Leach Research Station since 1998. He received his bachelor's degree in history at the University of Chicago and his doctorate in plant breeding and genetics/horticulture from Michigan State University. Work at the Leach Station centers on the development of ornamental rhododendrons that are adapted to difficult conditions. Research in support of this goal includes investigations of cold and heat tolerance, identification and transfer of disease resistance, and adaptations to brighter (sunnier) growing conditions.


Sarah Kyker, PhD, is a microbial ecologist interested in the influence of human and natural environmental changes on microbial communities and their function. Kyker received bachelor's degrees in botany and secondary education from Miami University (Ohio) in 2003. Her graduate work was conducted in biology at Case Western Reserve University and resulted in a master's in 2006 and a doctorate in 2010. Sarah has been with The Holden Arboretum since 2007, where she completed her doctoral research under the advisement of Research Department Chairman David Burke. She is currently a postdoctoral scholar at Holden working with Burke and scientist Kurt Smemo.


Eva Rodriguez is a two-year intern in the Education and Public Programs Department. Rodriguez assists with interpretive projects, exhibit development and school and adult programming.


Ann Rzepka, horticulturist at The Holden Arboretum since 2008. Rzepka maintains the Myrtle S. Holden Wildflower Garden, collects and propagates seed for use within the garden, assists conservation staff with the heritage species monitoring program, and helps maintain Holden’s commitment to the Center for Plant Conservation and the preservation of rare and endangered plant species. She was previously employed by the Geauga Soil and Water Conservation District where she served as their Natural Resources Specialist. She earned a bachelor's degree in environmental studies from Hiram College.


Kurt Smemo is an ecosystem ecologist at The Holden Arboretum and an adjunct assistant professor at Case Western Reserve University and Michigan State University. His studies involve how soil microorganisms control organic matter decomposition and nutrient availability in forest and wetland ecosystems, and how those organisms respond to environmental change. Smemo has earned his bachelor's degree in forestry at the University of Montana, his master's in environmental science at the University of Illinois and his doctorate in ecology from Cornell University.


Susan Swisher, Holden's librarian, is a Northeast Ohio native who received her master's in library science from Case Western Reserve University. She began her career as a reference librarian at the Cuyahoga County Public Library. She spent several years in San Diego managing a cooperative library system before returning to Ohio.


Rebecca Thompson, Growing Students and Science program coordinator, has been with the Education Department at Holden since 1999 and has worked in environmental education for many years. She coordinates the Growing Students and Science Program, a community partnership to build interest and ability in the sciences in public school systems, and leads Holden’s Junior Birders Club for children and teaches a number of children’s classes. She received her bachelor's degree in biology at Kent State University.


Charles Tubesing, chief horticulturist, is a graduate of Purdue University. Tubesing has been with Holden since 1986. He is responsible for the development of Holden’s plant collection, having extensive experience and interest in the selection of appropriate woody plants to fit specific landscape criteria and in plant propagation with a special interest in magnolias.


Michael Watson, conservation biologist, started at Holden as a conservation seasonal three years ago. He earned his bachelor's degree in biology from the College of Wooster and his master's in ecology and evolutionary biology from the University of Michigan. He spends most of his time on the deer browse project, a large-scale, long-term study attempting to measure the impact of deer on Holden's forests. He is also the coordinator for Holden's Bluebird Project, which relies on 50 volunteers to monitor and band bluebirds, tree swallows and other secondary cavity nesting birds that use more than 200 nest boxes on the Holden properties.


Marian Williams, manager of public programs, has been with Holden since 1987 and is responsible for Holden’s public programs and interpretation of the gardens and natural areas as well as a variety of other special projects. She received her undergraduate degree from Earlham College and her master’s degree from Purdue University.


Greg Wright, nursery supervisor, is in charge of plant propagation at Holden. He earned his bachelor's degree in horticulture at Brigham Young University and his master's degree in landscape architecture at Utah State University. Wright has been with Holden for eight years and teaches a variety of classes on horticulture and landscape architecture.

Non-Staff Instructors

Ian Adams is an environmental photographer, writer, and teacher specializing in natural, rural, historical and garden areas in Ohio. Since 1985, more than 7,000 of his color photographs have been published in books, posters, calendars, magazines and other publications. Ian has published 19 photography books and conducted more than 200 photography workshops and seminars. His books include The Holden Arboretum (University of Akron Press, 2000), Backroads of Ohio (Voyageur Press, 2006), Our First Family's Home: The Ohio Governor's Residence & Heritage Garden (Ohio University Press, 2008), Missouri Botanical Garden: Green For 150 Years (Missouri Botanical Garden Press, 2008) and A Photographer's Guide to Ohio (Ohio University Press, 2011) He lives in Cuyahoga Falls with his tabby cat, Fuji.


Jill Anderson, PhD. Anderson’s research examines the consequences of global climate change on plant ecology and evolutionary processes in both temperate and tropical systems. Her research explores the effects of a warming world on plant reproduction and flowering, and how climate change may bring about shifts in the range of many species, especially in mountain systems in the American West. Anderson’s research on Drummond’s rock cress (Boechera stricta), a small mustard native to the Rocky Mountains of Colorado, was recently featured in Science News.


Pat Biliter comes from a long line of eastern Kentucky coal miners and broke family tradition to become a geologist. After completing his undergraduate and graduate studies at the Ohio State University and UCLA, and Airborne and Ranger training at Fort Benning, Ga., Biliter spent the next 30 years overseas working for the Army Corps of Engineers. Among other assignments, he served as the Deputy District Engineer of the Europe District in Wiesbaden, Germany, where he was responsible for military construction, humanitarian relief and host nation assistance in 90 European, African, Middle Eastern and southwest Asian countries. After retiring from federal service in 2001, he settled in Cleveland, Ohio, and within a year became a school guide at the Holden Arboretum. Inspired in high school by the writings of John Muir and Rachel Carson, Pat quickly realized that the Holden Arboretum was a perfect setting to share his lifelong love of natural history and conservation with coming generations of young Americans. Biliter is also an Ohio Certified Volunteer Naturalist.


Denise Brown is a registered yoga and tai chi instructor with many years of experience as well as personal practice. She truly believes everybody can benefit from yoga and tai chi regardless of body type or experience level. Hailing from Surrey England, she picked up her first yoga book at the age of thirteen. As she moved around the world she continued to follow her love of yoga. Landing in Cleveland Heights, Ohio, Brown studied with the American Light of Yoga Society and Alice Christensen where her teaching roots were developed. She then pursued her formal teacher training with Joseph le Page, founder and director of Integrative Yoga Therapy (IYT) in 1999.


Judy Churchill, AYT, RYT, CYT, an accredited yoga teacher of Satyanada Yoga and registered as an RYT at the 500-hour level with Yoga Alliance. In 2001, she received formal initiation in India from Swami Niranjanananda Saraswati and given the spiritual name, Jayasri. She later earned a level two accreditation from Satyananda Yoga Academy, Mangrove Mountain, NSW, Australia. Churchill maintains a website with book reviews and articles on yoga at www.yogic-wisdom.com


Dan Donaldson is the District Administrator of Lake County Soil and Water District. Having earned his bachelor's degree in Environmental Management from Cleveland State University, Dan assists local governments, landowners, and partner agencies with natural resource planning objectives, including special projects, ordinances, programs, conservation easements, program planning, administration, and grant writing.


Rebecca E. Drenovsky, PhD, is a plant biologist whose research investigates how interactions between plants and the soil environment affect plant ecology and physiology. Her research explores how plants acquire and store nutrients, and how nutrient limitation affects ecological processes. Her research also examines the factors that allow some species to become invasive. Drenovsky’s research is important given current pressures on native environments resulting from human environmental alteration and species invasion.


Denise Ellsworth, directs the honeybee and native pollinator education program through the OSU Department of Entomology on the OARDC campus in Wooster. In this outreach position, she supports and teaches beekeepers, farmers and gardeners through a variety of workshops, written materials and electronic resources. She earned her master's at Ohio School of Natural Resources and bachelor of science from Ohio State University's Department of Plant Pathology. She is also a garden writer for the Akron Beacon Journal.


Bob Faber has been a consultant to conservation and environmental organizations throughout the region. He leads natural history programs across the United States.


David J. Nowak, PhD is a research forester with the Forest Service’s Northern Research Station and project leader for the Urban Forests, Environmental Quality and Human Health program. The goal of Nowak’s research is to investigate the plant community composition in urban areas and identify the environmental or ecosystem services these plant communities provide. Nowak is also involved in developing tools that can be used to aid in management and planning decisions that sustain urban forest health and services.


Stan Plante has been birding for more than 40 years. At the age of eight, his birding career began by following the examples of his mother. He is also an Ohio Certified Volunteer Naturalist through the Holden program, and periodically leads natural area tours. He has birded throughout the continental United States and in Asia, the Caribbean, Europe and the Middle East. Plante is a water resources engineer during the work week and resides in South Russell with his wife Julie and four children.


Lisa Rainsong holds a doctorate of musical arts in composition from the Cleveland Institute of Music, is a member of CIM’s music theory faculty and is also a professional soprano as well as a teacher and composer, She also earned a naturalist certificate from the Cleveland Museum of Natural History, where her study focused on field experience. She records bird songs and the songs of crickets and katydids as part of her field research and presents programs on bird song and insect song across the state. Her recordings and photos – including birds and insects found at Holden - can be found on her blog, Listening in Nature at listeninginnature@blogspot. com.


Gunter Schwegler is a fiber artist specializing in silk painting. His work in watercolor, acrylic and oil painting formed the basis of his style and technique. His recent work includes framed silk paintings, wearable art, banners, stage and set design, home furnishings, CD covers and public art space. His work is featured in “Creative Silk Painting” by Jan Janis and Diane Tuckman.


Barbara Tercek, RYT, a certified yoga instructor and social worker is studying for her certification in yoga therapy.