The Plant a Trillion Trees Podcast

John Grimshaw has been interested in plants his entire life, as both gardener and botanist. He holds a first class degree in botany and a doctorate in the ecology of the forests of Mt Kilimanjaro from Oxford University. His Tanzanian connections remain important, and he’s proud to be an honorary elder of the Maasai community of Lerang’wa, Tanzania. African plants remain an important botanical inte...

Richard McCoy is a 30-plus-year green industry professional, American Green Zone Alliance (AGZA) Northeast Regional Representative and owner of Richard A. McCoy Horticultural Services Inc. established in 1995 and incorporated in 1998 as a conventional landscape company. McCoy’s company began a transition to become one of New Jersey's first completely organic, ecological, and low-impact land ca...

Mark Richardson is the Director of Horticulture for the New England Botanic Garden at Tower Hill in Boylston, Massachusetts. He leads a team of horticulture staff and oversees a living plant collection that spans sixteen distinct garden spaces, two conservatories, and over 100 acres of surrounding woodlands and wetlands. He has a passion for ecological horticulture and native plants, and he lectur...

Tim Boland is the Director of the Polly Hill Arboretum on the island of Martha’s Vineyard, West Tisbury, Massachusetts. Tim moved with his wife Laura and two children to the Vineyard in 2002. Before his move to the Vineyard, he was Curator of Horticulture at the Morton Arboretum in Lisle, Illinois.  A plantsman with wide-ranging interests, he is a nationally recognized author, photographer, and le...

Jason Ross is the Managing Publisher of Wood Central - the world's largest news platform for forest-based news!  Wood Central has more than 170,000 users, with over 75% of users under 45, and 47% under 35! We cover all the news on the Wood Central website, across all media channels that interest our users, with fresh content from across the world updated all day, every day. So whether it's...

Alec Charais is one of the most passionate people in horticulture today. Having grown up on a family farm, his love for plants grew into a rewarding career that today finds him collaborating with breeders and agents across the globe, searching for trees and shrubs that will beautify the outdoor living experience for everyone.   At Bailey Nurseries, a family-owned fifth-generation nursery with grow...

Hal and I talk about some of the highlights of the podcast thus far. We think you will enjoy the overview if you have never listened to our podcast before. Below you will find a short list of some of the podcasts that you might want to listen to or relisten to – to see how our guests are making a dent in the climate crisis by their positive actions. We are grateful to all of our guests for sharing...

Seth Lieberman co-founded Quiet Clean Philly; an all-volunteer organization dedicated to phasing out gas leaf blowers in the City of Philadelphia.  Seth’s activism and articles on the harms of gas leaf blowers have been featured in the  Philadelphia Inquirer , WHYY’s  Studio 2  and  Radio Times , Channel 6 ABC Action News,  The Chestnut Hill Local ,  The Weavers Way Shuttle ,  Planet Philadelphia...

Ron Kinney is the production manager at Monrovia’s Oregon nursery. Ron has a degree in Ornamental Horticulture from California State Polytechnic University and has been in the industry for more than 30 years. Part of his role as production manager includes responsibility for tree production, both in containers and in-ground field production, at Monrovia’s California and Oregon nursery facilities. ...

Ari Miller is the director of design at Hinge Collective in Philadelphia, Pennsylvania, a public interest design firm that puts community engagement and public participation at the forefront of their practice. As both a landscape architect and arborist, Ari has always advocated for the integration and restoration of natural systems in urban design. Over the course of his 17-year career, Ari has wo...

Steven Kiiskila is the Crop and Growing Team Manager at Arbutus Grove Nursery, located at the southern tip of Vancouver Island, British Columbia, Canada. Each year his team grows 15 million container seedlings composed of 18 or more species, primarily for reforestation throughout Western Canada and the Pacific Northwest. He has been involved in reforestation his entire career; from collecting seed...

Joe Lamb, founder of the Borneo Project, is a writer, activist, and arborist living in Berkeley, California. His poetry and essays have appeared in Earth Island Journal, The Sun, Caliban, Wind, Orion, and other magazines. His work is also included in the anthologies The Rag and Bone Shop of the Heart: A Poetry Anthology, Robert Bly et al editors, and Veterans of War/Veterans of Peace, Maxine Hong...

Mark Krawczyk is an applied ecologist, educator, and grower with a background in permaculture design, agroforestry, natural building, traditional woodworking, and small-scale forestry. He co-owns and operates Keyline Vermont LLC, teaching, designing, and consulting for farmers, homeowners, and homesteaders. Since 2008, Mark has taught over 30 Permaculture Design Courses and been a specialist guest...

Asha-Lé Davis joined the Pennsylvania Horticultural Society (PHS) as Trees Specialist in 2021 to pursue her passion for empowering people to grow tree canopy in their communities. Since joining, she has helped grow the PHS Tree Tenders program in Bucks, Chester, Delaware, and Montgomery counties to over 60 active groups who have planted 3,000+ trees. She recently took on the role of facilitating t...

Paul Hickman is the founder of Urban Ashes a pioneering company that advocates for urban wood utilization. The company transforms fallen urban trees into valuable local resources. Urban Ashes designs, develops, and implements urban wood utilization for infrastructure in collaboration with municipalities, local organizations, and businesses to support the local community.   In addition to salvaging...

David Teuschler is the Chief Horticulturist for Devil Mountain Wholesale Nursery. He established the nursery’s propagation program and currently directs the propagation and inventory teams for the company’s sixteen locations across California. David has worked in the nursery industry for three decades, including many years at Valley Crest Tree Company. While there, he served as Plant Health Care M...

Matthew Aghai is a dedicated reforestation expert, applied scientist, and executive leader at Mast Reforestation. He currently serves as the VP of Research and Development at Mast Reforestation, General Manager of Cal Forest Nurseries, and Advisor to Silvaseed Company. His recent work focuses on scalable solutions for mitigating climate change through the development of new initiatives to moderniz...

Kim Shearer is the Curator of Living Collections and Manager of the Haerther Charitable Trust New Plant Development Program at The Morton Arboretum. In her role as curator, Kim focuses on the development and maintenance of resilient living collections that provide a germplasm resource for researchers and plant breeders seeking to address the issues of climate change; while also working with the co...

Kristen Pullen completed her Bachelor of Science degree in Biology at Rider University. After university, she took an internship position at Longwood Gardens in Kennett Square, Pennsylvania. The internship focused on all research aspects of the public garden from tissue culture to new plant evaluation and selection. Kristen has been with the new product department at Star® Roses and Plants since 2...

Lars Peter Jensen is originally from Denmark and arrived in the U.S.A. in 2003 and settled in Brevard County Florida where he lives with his wife and three children. Lars is the head of sales, marketing, and business development and part owner of the Blackmore Company. Blackmore has been instrumental in the horticulture industry for more than 50 years. His company holds a patent for the Air Tray®...

Kathy Jentz is the editor and publisher of the award-winning Washington Gardener Magazine, based in Washington, DC. She is also the editor of three plant society journals: the Water Garden Journal (IWGS), The Azalean (ASA), and Fanfare (Daylily Society Region 3). Jentz hosts the popular GardenDC Podcast, which was recently named Best DC Podcast. She is also co-author of The Urban Garden: 101 Ways...

Kristin Ohlson is a writer from Portland, Oregon. Her new book  Sweet in Tooth and Claw: Stories of Generosity and Cooperation in the Natural World  – which the Wall Street Journal calls “excellent and illuminating”--probes the mutually beneficial relationships among living things that undergird the natural world.  Her last book was  The Soil Will Save Us: How Scientists, Farmers and Foodies are H...

Nykia Perez Kibler, co-founder of Philly Tree People (501c3), is an ISA Certified Arborist® with a Master in Environmental Studies degree with a focus on Environmental Biology from the University of Pennsylvania (Penn). She also has a Master in Liberal Arts from Penn, a Certificate in Landscape Plants from Temple University, a Master of Library & Information Science from The University at Buff...

Since April 2016, Craig Roncace has been the Urban Park Manager for the University of Pennsylvania. The Urban Park Department consists of five shops, each with its own Supervisor, and 58 staff who represent two unions. The Urban Park operation covers campus landscaping/maintenance, athletic field management, Penn Park, all hard surface maintenance, and the campus-wide waste/recycling program. Befo...

Markku Koivisto keeps an ear to the ground and an eye to the sky, connecting the needs of organizations around the world with the power of drone data. As Chief Business Development Officer, he combines analytical expertise with a can-do attitude to ensure GLOBHE delivers the right data to the right customer at the right time.  While a young industry, Markku brings many years of experience in devel...