Andy Lipkis

Andy Lipkis is a practical visionary who has dedicated his life to healing the environment and improving the lives of individuals and communities.  In 1973, at the age of 18, he founded TreePeople, an organization that inspires and supports the people of Los Angeles to come together to plant and care for trees, harvest the rain, and renew depleted landscapes.

Jeff Reimer

Jeff Reimer earned his BS in Forestry and MS in Urban Forestry from Cal Poly, San Luis Obispo where he works in the Natural Resources Management and Environmental Sciences Department. Jeff is passionate about the need for education and accurate information relating to trees and their appropriate selection. He actively develops and maintains the online Urban Forest Ecosystems site, is certified by the Society of American Foresters, and serves on the California Urban
Forestry Advisory Committee.

Jennifer Nelson

Tualatin Soil & Water Conservation District

Jennifer Nelson has a MS in Environmental Science from the University of Illinois. She is the Outreach, Volunteer, and Education Program Manager for the Tualatin Soil and Water Conservation District, where she connects with the public at events and classes as well as on the District website at and on and various social media channels (Facebook/tualatinswcd, Twitter @tswcd). Jennifer enjoys working through the challenges of her own backyard native gardening project.

Mary McKenna

Mary McKenna has a BS in Biology from Cal Poly, San Luis Obispo, and a MA from UC Davis in Microbiology. She taught Biology at Gavilan College in Gilroy, California from 1979 to 2011 when she retired a bit early to go on a trek in Nepal. Since then, Mary has worked to help to establish the Ray Williams Arboretum at Gavilan. She lives, hikes, and gardens in Aptos, California, with her husband, Jim, and their dogs, cats, chickens, and horses.

Jim Gersbach

Jim Gersbach has been involved in planting, planning, and caring for Portland’s urban forest for 25 years. He created the Parklane Global Forest in east Portland in 1999, and the Linear Arboretum in northeast Portland in 2005. Catch up with Jim at one of his topical tree tours at Hoyt Arboretum and in various Portland parks and neighborhoods, or at one of his public presentations on urban tree diversity for the Northwest.

Devaki Bhaya

Devaki Bhaya grew up in India and was an undergraduate at Presidency College, Calcutta. She got her PhD in Biochemistry from Cornell University before returning to India as a founding faculty at the Centre for Biotechnology JNU, Delhi. She is currently a Staff Member at the Carnegie Institution for Science and a Courtesy Professor in the Department of Biology at Stanford University. Her research interests are in understanding how microbes respond and evolve in a
changing environment.

Sean Hogan

Cistus Design & Nursery

Sean Hogan has been involved in horticulture since about 18 months of age and seriously since the age of three. He served as horticulturist at the UC Botanical Garden at Berkeley and is now owner of Cistus Design and Nursery, specializing in plants from all over the world, especially western natives, and designing public and private gardens on the West Coast and beyond. Sean is the author of Flora: A Gardener’s Encyclopedia and Trees for All Seasons: Broadleaf Evergreens for Temperate Climates, both from Timber Press.

Ann Northrup

Ann Northrup spent her undergraduate years at the University of Michigan, where she earned a Bachelor of Science in microbiology. Her interest in plant pathology started there, but she took a five-year diversion to work in the field of medical diagnostics at Bio Rad Labs in Richmond, California, and another two years as a molecular biology research assistant at UC Irvine. Returning to plant pathology, Ann earned a master’s degree UC Berkeley. She has worked primarily in disease diagnostics of ornamental plants, first with Soil and Plant Lab in Orange, California, and then with Nurserymen’s Exchange in Half Moon Bay.

Ann currently consults privately in plant pathology and arboriculture and teaches horticulture classes at Foothill College in Los Altos Hills and Merritt College in Oakland. One of her professional pleasures is volunteering at the Sick Plant Clinic. She is also an active volunteer in the UCCE Master Gardener program for Santa Clara County. In her spare time, she enjoys playing her flute in a woodwind quintet in Saratoga and with the Saratoga Community Band conducted by her husband. And of course … she gardens.

Lorene Edwards Forkner

Lorene Edwards Forkner lives and gardens in Seattle where she pursues a good and delicious life filled with family and friends together with all things horticultural, believing that the really good part is in the blending of one’s passions.

Lorene is the author of five garden books including Hortus Miscellaneous (Sasquatch Books), Handmade Garden Projects, and The Timber Press Guide Vegetable Gardening: Pacific Northwest. Lorene is also the author of the newly released “Color In and Out of the Garden,” Abrams Books, 2022. Follow along at She was the editor of Pacific Horticulture from 2012-2019.

Dave Muffly

Dave Muffly is an ISA Board-Certified Master Arborist on the Canopy board of directors. A Stanford-trained mechanical engineer, he practices ecological horticulture in the Bay Area.

Richie Steffen

Richie Steffen is curator of horticulture for the Elisabeth C. Miller Botanical Garden in Seattle, where he manages the rare plant collections and leads the acquisition of new plants. Richie is co-author of The Plant Lover’s Guide to Ferns from Timber Press. He is an active member of numerous horticultural societies in the area and lectures widely about garden-worthy plants.

Craig Latker

Craig Latker attended the University of California at Davis and Berkeley, receiving a degree in Landscape Architecture from Berkeley in 1983. He has over 20 years experience working as a landscape designer.

He has worked at a large interior landscape installation company and a boutique landscape design firm specializing in large estates and country homes. Seven years ago he founded Latker Design Solutions, where he specializes in residential projects of varying size. Craig has expertise in a wide range of design styles — from classic Provencal and English cottage, to mid-century modern, to ultra contemporary.

Craig is also a professional illustrator and designer, and has done work for non-profit organizations and publications such as Pacific Horticulture, the Nature Conservancy, Strybing Arboretum, and the University of California at Davis.

Frederique Lavoipierre

Frederique Lavoipierre is the creator and author of “Garden Allies,” a series that ran for 10 years in Pacific Horticulture magazine. She also teaches classes and workshops on sustainable landscaping, including ecological principles, habitat gardens, beneficial insects, soil ecology, freshwater ecology, and aquatic invertebrates. Follow her on Facebook at