Green Tree World – Master Arborist Tree Care Rooted in Art, Science, and Nature
Green Tree World is the creation of Gary Walker, a renowned ISA Master Arborist and Master Gardener with over 30 years of professional experience in tree care and garden design. A lifelong student of Dr. Alex Shigo, one of the most influential figures in modern arboriculture, Gary combines deep scientific knowledge with artistic sensibility and horticultural expertise. Licensed, bonded, and fully insured, Green Tree World offers San Diego-area residents a level of care that harmonizes nature, safety, and design excellence.
Expert Tree Services With an Artistic Vision
Green Tree World provides professional pruning, tree removal, and holistic landscape consultation guided by Gary Walker’s extensive academic and hands-on background. With training from Harvard, UMass Boston, and Emerson—and accolades including a San Diego Home & Garden Magazine Grand Prize—Gary approaches tree care with precision, creativity, and environmental respect. Clients benefit from thorough site assessments, personalized recommendations, and services rooted in decades of real-world expertise and international research.
A Life Devoted to Trees, Gardens, and Community
Gary Walker is more than an arborist—he’s a teacher, radio host, and naturalist whose private garden is listed in The Garden Conservancy’s national registry. His public speaking, media presence, and award-winning garden designs have inspired countless homeowners to rethink how trees enhance their lives. With a reputation built on education, artistry, and trusted craftsmanship, Green Tree World is a unique and highly regarded choice for elite tree care in Southern California.
Best plant / tree expert for any job!! Call Gary! When my large boxed palm trees were struggling a few years ago, I called Gary and he offered me a reasonable priced option to help them thrive. They rebounded quickly and Gary has been helping me with my indoor and outdoor palms ever since. He’s a trusted expert and has reasonable options for your tree and plant needs. Highly recommended!!
After 12 years of neglect our 9 Melaleuca trees were in dire need of some help. The natural sculptural elements of the trunks and branches had become completely obscured. The trees had grown together forming a thick hedgelike appearance blocking much of our beautiful view. With the eye of an artist, Gray Walker was able to Trim, Lace and Shape them into the vision we had hoped to eventually achieve when they were originally planted. Additionally, providing them all with a deep fertilization and giving us clear watering instructions moving forward, we were very pleased with a job very well done! Thanks Gary!
I called Gary in the morning and expressed my concern over a black spot I saw on my beautiful Chilean Mesquite tree. He was at my house a few hours later, put my mind at ease and implanted an organic deep root fertilizer. He also trimmed my lace bark elms and fertilized them as well. It struck me that Gary doesn’t just do this for a living. He genuinely loves trees and wants to see them thrive. He is the tree whisperer.
Gary knows trees, and did a beautiful job trimming and feeding several of ours. They look much more "tree-like" now, and he got rid of the branches that were encroaching on the house. He cautioned us that our initial instinct on pruning wasn't in the trees' best interests, which we appreciated (we want our trees to be happy). He saw that our magnolia was doing poorly (we thought it was supposed to be light green) and fertilized it. It looked better the next day, already a deeper, lusher green.
Gary did a beautiful job of lacing our olive tree. It was badly in need of a trim/clean up because I hadn’t been able to find someone I felt I could trust and who knew what they were doing. I had the utmost confidence in Gary.