Unparalleled knowledge and experience!
Roger Hartzog, Principal
Roger is an International Society of Arboriculture (ISA) Certified Arborist (WE-14586A) and an Environmental Engineer, having graduated from the University of Florida School of Forest Resources as a Natural Resources Manager and attended the School of Graduate Studies in Environmental Engineering. He subsequently worked with the U.S. State Department in Central America on programs involving water resources and engineered environments. He managed the CWA Section 208 Water Quality Management Program for the State of Louisiana until accepting an Attorney General’s appointment as Executive Director of the Western States Project, a multi-state and international environmental protection program headquartered in Phoenix. Over the past two decades Roger has served as a real estate Broker, a licensed investment advisor, and a certified Community Manager. He is an experienced Writer and Copywriter in the environmental and green industry, developing online content, market messaging, blog posts, email campaign material, and newsletters. He founded Tree Theory Green Assets Management consultants in 2017.
Juan Barba , Certified Arborist
Juan graduated from the University of Arizona with a B.S Degree in Landscape & Environmental Horticulture. Juan is An ISA Certified Arborist, native of Tucson, with 40+ years of experience throughout Arizona and several other states. He has practiced in and instructed all facets of arboricultural & horticultural care, and is a past president of Western Chapter, ISA as well as a former chair of Trees for Tucson. For 20 years Juan provided a monthly column on professional tree climbing and desert arboriculture for the premier regional magazine, Southwest Trees & Turf. Juan Barba has been a southern Arizona Consulting Arborist since 1989.
Doug Donahue, Irrigation Systems Expert
Doug Donahue is Tree Theory's resident expert in all things to do with landscape irrigation. With more than 40 years of experience with irrigation systems, including commercial, private residential, and HOA properties, Doug has comprehensive knowledge of every type of irrigation system, all component parts and brands, and their proper functioning. He performs system inventories and audits for Tree Theory clients who want an accurate third-party independent assessment of their systems and seek recommendations on how to improve efficiency to save on water costs.
Kristen Battafarano, Horticulturist and Certified Arborist (WE-14296A)
With over 20 years as a horticultural professional in the Sonoran Desert, Kristen Battafarano brings a wide range of plant knowledge to the Tree-Theory team. In addition to managing a 30-acre desert plant nursery, Kristen has been a desert gardening instructor at the Desert Botanical Garden, landscape maintenance supervisor, landscape designer, and Plant Biologist for the National Park Service. When she isn’t evaluating the health and care of landscapes throughout the region, she enjoys growing food in her organic urban garden, which has been toured by over 600 fascinated visitors.
Jacob "Jake" Flater, Certified Arborist
Jake has been an ISA Certified Arborist (WE-9092A) since 2008, having studied biology and computer technology at Estrella Community College and Arizona State University. As well, he has been involved with Urban Forestry, GIS tree labeling and map building, Soil Building and Nutrients, Water Harvesting, Biochar, and Composting. Over the years Jake has worked with a number of professional landscaping companies and nurseries as both a plant health advisor and certified arborist.
David Hartzog, IT Systems Manager
David is Tree Theory's Manager of Information Technologies. He's a graduate of Estrella Community College in Computer Networks, and he graduated from Arizona State University with both a Bachelor's Degree and Master's Degree in Computer Systems Engineering. He is an accomplished mobile applications developer, having created Tree Theory's proprietary field inspections and GIS-based tree inventory and mapping systems that support all field data collection and reporting.
Daniel Escalante, Horticulturist
Daniel graduated from California Polytechnic State University in Pomona with a degree in ornamental horticulture. He has been active in the nursery/landscape industry for over 36 years. Daniel is a certified Nurseryman in two states, is Water Wise certified, SLM certified, and is a fluent Spanish speaker. His outside interests include sharing his certified therapy dog Sofie in a hospital setting, escaping Valley’s brutal summer heat in the beautiful norther Arizona town of Payson, deep sea fishing, travelling to new places with his bride of 34 years, who shares the same interests! The dream of Daniel and Lupe is to one day reside in the mountain community of Payson!