Ray Sumner, born Catherine Ray Martin on 21 March 1944, grew up in Townsville, Queensland. She attended the University College of Townsville (now James Cook University) on a partial scholarship from the Department of Education, designed to address a shortage of teachers. As part of the scholarship's terms, she spent a year at a teachers' training college in Brisbane before returning to Townsville to teach high school for at least two years. She taught German, geography, maths and English, saving her earnings to travel Europe for several years. Upon returning to Townsville, she completed her studies at night while teaching during the day, earning a degree in Geography in 1972 and a Master of Geography in 1975.

After working in various locations along Australia's east coast, including at the University of Newcastle, Sumner received a scholarship from the National Museum in Victoria to research German naturalist Amalie Dietrich in 1980. This research became the foundation of her PhD (1986) in the Department of History at The University of Queensland, under the supervision of John Moses.

As a geography professor, Sumner specialised in the social and environmental impacts of science and technology, as well as the built environment and history of tropical Queensland. She held a teaching and research position at the Queensland University of Technology before relocating to the United States when her engineer husband was offered a job at the California Institute of Technology. In the U.S., she held teaching and research positions in geography at California State University, Dominguez Hills, and Long Beach City College, where she worked for about twenty years. She was also involved with a local branch of the Society of Women Geographers and the California Geographical Society. Now retired, she continues to reside in the United States.

Melbourne-based Robin Michael Youl is a retired forester who was involved in farm forestry, revegetation, urban ecology and community initiatives from 1981 until 2009. During his career, he collaborated with various Victorian government environment departments, Greening Australia, Conservation Volunteers Australia, and most notably, Landcare Australia Limited (LAL), to which he was attached for over thirteen years. In recognition of his contributions to land care and the environment, he was awarded the Order of Australia Medal in 2012. He also led Australian Landcare International for a decade before stepping down in the 2010s. Together with his family, Rob manages 268 hectares of bushland around St Arnaud, Victoria, focusing on habitat conservation, revegetation, carbon storage and restoring pond chains. He has published several works on forestry, land care and other topics. Passionate about art, he explores environmental and architectural themes through painting, sketching and other creative forms.

Was involved in celebrations for the 200th anniversary of the birth of Amalie Dietrich in Siebenlehn, Germany, the birthplace of Dietrich.

Was involved in celebrations for the 200th anniversary of the birth of Amalie Dietrich in Siebenlehn, Germany, the birthplace of Dietrich.