Our Story

 Aspen Center for Environmental Studies (ACES) was founded by Elizabeth Paepcke in 1968. Elizabeth and her husband Walter came to Aspen from Chicago following World War II. In addition to ACES, the Paepcke family also established the Aspen Music Festival and School, The Aspen Institute, and co-founded the Aspen Skiing Company.


In 1969, Elizabeth Paepcke donated her 25-acre property in the West End of Aspen for the development of an environmental center and preserve. She was motivated by "The Aspen Idea” of harmony between mind, body, and spirit, and envisioned a place that would provide a bridge to nature for an increasingly urbanized society, while also serving as a sanctuary for wildlife in the heart of Aspen. As a child, Elizabeth had also been influenced by her experiences with Enos Mills, the father of Rocky Mountain National Park.

Elizabeth Paepcke was joined in her efforts by a number of founding trustees, notably science teacher Bob Lewis and botanist Stuart Mace. Together, they hoped that the nature center would provide programs in ecology and natural sciences for everyone, from school children to leaders and decision-makers.

In 1975, Jody and Tom Cardamone came to live at Hallam Lake, with Jody becoming ACES’ first Executive Director. Tom and Jody eventually became co-Directors and, over their first fifteen years, developed an education program in partnership with local schools, as well as the Naturalist Field School. In 1990, Jody stepped into her preferred role as Head Naturalist, and Tom stayed on as Director. 

For the next few decades, Tom led the organization through steady growth, including the development of ACES' programming at four primary sites: Hallam Lake, Rock Bottom Ranch, The Catto Center at Toklat, and Spring Creek. In the summer of 2012, Chris Lane was appointed as Chief Executive Officer and Tom transitioned into the role of President and Chief Ecologist, then retired from ACES.

Since then, ACES has expanded its environmental education reach to schools from Aspen to Rifle, partnering with more than 60 schools to provide education programs in the classroom and field. In addition to science education, ACES also focuses on sustainable food systems and regenerative agriculture, forest health, habitat restoration, and connecting adults and children to nature. In the next 50 years, we will continue to build a community of ecologically literate citizens, aiming to be a beacon of science-based environmental leadership and education for all ages, creating a deeper connection between humans and the natural world.

Our Mission

Inspired by the words of our founder, Elizabeth Paepcke, ACES’ mission is “educating for environmental responsibility.”


Aspen Center for Environmental Studies (ACES) is a nonprofit environmental science education organization. Since 1968, ACES has inspired a life-long commitment to the earth by providing innovative and immersive programming for all ages. We have three locations: Hallam Lake, Rock Bottom Ranch, and Catto Center at Toklat. Our programs focus on ecological literacy, regenerative agriculture, forest and ecosystem health, land restoration, and environmental leadership. 

ACES works to contribute to a national agenda for increased environmental awareness. Our programs reach over 140,000 individuals every year. We teach daily in schools from Aspen to Rifle, provide kids camps, adult classes, guided hikes and field programs for all ages, with 70 partner organizations. We also engage our community by hosting public lectures and events. ACES collaborates with land trusts, public agencies, and other nonprofits to achieve our mission.

In the next 50 years, ACES seeks to cultivate a community of environmental stewards so that children, parents, consumers, decision-makers, and leaders can make informed decisions in an increasingly complex world.