2026 12th Annual Tree Diversity Conference Presented by Bartlett Tree Experts
Price: $105 Public, $95 Member*, $65 Student
*Promotional price available to all members of Colorado Nursery & Greenhouse Association, Colorado Tree Coalition, and American Society of Landscape Architecture.
Note: A recording of the symposium will be available to all program participants for 14 days following the program date.
12th Annual Tree Diversity Conference Agenda
8:30 a.m. - Welcome
Phillip Douglas, Director of Horticulture and Center for Global Initiatives and Bartlett Tree Experts
8:35 a.m. - The Living Rooftop: Evolution. Stewardship, and Innovation at Millennium Park
Kathryn Deery, Director of Horticulture for Lurie Garden and Millennium Park
9:30 a.m. - Establishing Your Tree Legacy
Nicholas A. Martin, Vice President of Consulting, Bartlett Tree Experts
10:30 a.m. - 10-Minute Break
10:40 a.m. - Growing Together: Cultivating Urban Landscapes Where People and Plants Thrive
Grace Manning, Beltline Arboretum Senior Manager at Trees Atlanta
11:50 a.m. - Lunch
1:40 p.m - Help Us Plan(t) for the Future: Updates on the Denver’s First Urban Forest Strategic Plan
Elizabeth Judd, Urban Forestry Planner, Office of the City Forester, Denver Parks and Recreation and Luke Kiloran, City Forester, Office of the City Forester, Denver Parks and Recreation
2:40 p.m. - Pride and Prejudice or Trials and Tribulations: Bringing the diversity of western adapted trees into practical production
Sean Hogan, Owner of Cistus Design Nursery
3:40 p.m. - Closing Remarks
By Sonia John, Chair, Tree Diversity Committee
Talk Description and Speaker Biographies
The Living Rooftop: Evolution, Stewardship, and Innovation at Millennium Park
From its origins as a network of rail lines and surface parking lots to a premier 24.5-acre urban sanctuary, Chicago’s Millennium Park—and the renowned Lurie Garden within it—represents groundbreaking design and engineering. Today, this iconic rooftop park welcomes over 25 million annual visitors, serving as a vibrant stage for public art, free cultural programming, and inspiring landscapes.
Now in its 22nd year, Millennium Park is entering a new chapter of intentional evolution. This session explores the delicate balance between design, function and ecological sustainability. Insights gained from the reimagining of the gardens surrounding Cloud Gate, observations from dedicated (and at times experimental) tree care and large-scale renovations currently underway within Lurie Garden will be shared.
This candid discussion highlights the unique successes and challenges of managing a complex, intensive rooftop park while looking toward the future of the urban landscape.
Kathryn Deery serves as the Director of Horticulture for Lurie Garden and Millennium Park. Driven by a passion for the vital role public gardens play in communities, she works to maintain the design integrity of Lurie Garden while facilitating its continuous evolution. Additionally, she ensures Millennium Park maintains a high standard of horticulture by prioritizing both its beauty and its ecological function.
Prior to her time at Millennium Park, Kathryn held positions in horticulture and public programming at the Chicago Botanic Garden. She began her career in habitat restoration, contributing to key efforts throughout the San Francisco Bay Area’s Golden Gate National Parks. Kathryn holds a Bachelor of Science degree in Environmental Science from the University of Michigan.
Establishing Your Tree Legacy
Have you ever thought about how you can create a legacy? Are there options besides providing funding or donations to an organization? Yes…with proper foresight, information and long-term care, your trees can become a legacy that you, your family and the community can enjoy for years to come.
Learn how to take a holistic approach to maintaining the trees in your landscape, from planting to mature tree care, so you can establish your own living legacy. The concepts of care assessment, species selection, soil and plant health, pruning and other tree care-related activities will be discussed.
Nicholas A. Martin is originally from midwestern Illinois and went to college at Southern Illinois University Carbondale, where he received a Bachelor of Science degree in Plant and Soil Science in 2006. He received a Master of Science degree in Forestry and a minor in Urban Forestry from Auburn University in 2011. Nick has worked at Barlett Tree Experts for more than 15 years and is currently Vice President of Consulting. Nick is honored to work with consulting arborists throughout the United States, Canada and the United Kingdom. He also helps other Bartlett arborists gain a better understanding of the benefits of arboricultural consulting. An ISA Board Certified Master Arborist and Urban Forest Professional, Nick is also Tree Risk Assessment Qualified, Tree and Plant Appraisal Qualified and a Registered Consulting Arborist. He uses his knowledge and almost 20 years of experience to not only assist his clients with their consulting needs but also help support his fellow consulting arborists with their professional growth and clients’ needs. Nick lives in Algonquin, IL, with his wife, daughter and two dogs. He enjoys spending time with his family and dogs, working on home improvement projects and spending time outdoors improving his landscape.
Growing Together: Cultivating Urban Landscapes Where People and Plants Thrive
The Atlanta Beltline is one of the largest urban redevelopment projects in the United States: transforming a historic 22-mile railroad corridor into a network of parks, multi-use trails, future transit and green space that connects intown Atlanta neighborhoods and supports a more sustainable city. Along this corridor lies the Atlanta Beltline Arboretum, a living collection of trees, shrubs and native groundcover woven into an active urban landscape. First envisioned in 2005, the Arboretum is managed by Trees Atlanta in partnership with Atlanta Beltline, Inc., Atlanta Beltline Partnership and the City of Atlanta Department of Parks and Recreation. The Arboretum offers a unique lens into how plants, people, water, soils and changing weather patterns interact in a heavily used public space. This presentation explores lessons learned from managing an urban arboretum under constant use and highlights how thoughtful design and stewardship can balance public access with ecological care.
Grace Manning is the Beltline Arboretum Senior Manager of Trees Atlanta, where she oversees long term maintenance and collections development in the Atlanta Beltline Arboretum. With a background in plant biology from the University of Georgia, she brings experience in arboriculture, landscape management and community-focused public greenspaces. Her work centers on increasing plant diversity in urban settings and fostering meaningful connections between people and plants through inclusive, public-facing environmental programming. Docent training, volunteer engagement and summer Weeds & Wine program provide unique opportunities to engage communities in Atlanta's urban forest. Grace is an ISA Certified Arborist and is passionate about native plants and fostering meaningful connections between people and the natural world.
Help Us Plan(t) for the Future: Updates on the Denver’s First Urban Forest Strategic Plan
In June 2024, the Office of the City Forester finalized the city’s first Urban Forest Strategic Plan (UFSP). With a vision for social, economic and environmental health, the city has moved into implementation of this 20-year plan. A brief overview of the plan development process and final document will be presented along with a summary of what is complete, in progress and yet to begin. Details on early successes, including a Rotational Pruning Analysis, an Operations Assessment and development of a Partner Network working group will be celebrated. A transparent assessment of what is believed to be achievable and what currently seems like an ambitious or even unattainable goal will conclude the session.
Elizabeth Judd holds degrees in regional planning and landscape architecture and has been working in the semi-arid west for 20 years. After many years as the first Landscape Architect for Boulder, CO, she is now the first Urban Forestry Planner for Denver, CO where she is helping to develop and implement a vision for the urban forest and promote an integrated and equitable approach to growing the urban canopy. When not working, you can find her traveling, cooking, spending time outside and generally messing around with plants.
Luke Killoran is the City Forester for Denver’s Department of Parks and Recreation. His interest in forestry first sprouted as a kid climbing trees and grew even deeper during his college years at the University of Wisconsin–Madison and Colorado State University (Go Rams!). Today, Luke works to grow and diversify Denver’s urban canopy while protecting the mountain forests that make Colorado iconic. Whether he’s planting trees, leading outreach programs or shaping policy, Luke is committed to making Denver greener, healthier and more resilient for generations to come. And if you’re curious—his favorite tree? The swamp white oak (Quercus bicolor).
Pride and Prejudice or Trials and Tribulations: Bringing the diversity of western adapted trees into practical production
By nature, most western drought-adapted plants are still growing. It is difficult to achieve apical dominance. Discover learned techniques and some of the diverse plants now becoming available.
Sean Hogan is a design consultant, author and nursery owner. He was born in Portland and spent his later childhood years in Sacramento. He pursued his education in horticulture and botany at American River College and Sacramento State. Early work included mapping rare and endangered plants for the State of California as well as landscape and design work, often revolving around his love of western natives. He later worked as a curator at the UC Berkeley Botanic Garden. In 1995, he and his partner, UC Davis Arboretum Botanist Parker Sanderson, returned to Portland to start a design and consultation firm specializing in regionally appropriate plants for the Pacific Northwest. This eventually evolved into Cistus Nursery that has an extensive collection of rare and underused plants.
Sean has lectured extensively in North America and Europe, in addition to explorations of South America, South Africa and the western regions of the United States and northern Mexico. His writing and photos can be found in an extremely wide range of horticultural and botanical literature.