Over 100 years combined experience!


Rick Cober

Rick graduated from Arizona State University with a B.S. in Environmental Horticulture. A certified arborist (WE-3474A) with 40+ years of experience in Arizona & California building Nursery & Greenhouse facilities as well as consultant to developers, landscape professionals, and homeowner associations.  Rick is active with the ANA (Arizona Nursery Association) ALCA (Arizona Landscape Contractors Association) ACTC (Arizona Community Tree Council) and is a TREE Fund liaison board member for the WCISA (Western Chapter International Society of Arboriculture).


Roger Hartzog

Roger graduated from the University of Florida as a Natural Resources Manager and Environmental Engineer, attending the School of Graduate Studies in Environmental Engineering. Worked with the U.S. State Department in Central America on programs involving resources conservation and engineered environments. Directed the Water Quality Management Program for the State of Louisiana until accepting an Attorney General’s appointment as Executive Director of the Western States Project, headquartered in Phoenix and administering environmental projects in 9 States, 3 Canadian Provinces, and 2 Mexican States. Over the past two decades Roger has served as a real estate Broker, a financial advisor, and a Community Manager. 


Janet Waibel

Janet is the principal landscape architect at Waibel & Associates as well as being the author of SLM on top of that she is also a certified arborist.  She is responsible for project design and plan development.  Twenty years in the professional field of landscape architecture has afforded Janet the opportunity to establish numerous positive working relationships with many contractors, suppliers and professionals involved in the design and construction industry. Janet is a registered landscape architect in Arizona, with experience in the landscape design, planning and horticultural professions and has participated in all areas of the landscape and construction process from planning, conceptual design and layout stages, through preparation of construction documents and project implementation. 


Doug Long

Doug graduated from the University of Arkansas with a B.S. in Agronomy, studying soils and turf. With over 35 years of experience in the golf industry from being a Golf Course Superintendent, Golf Course Manager, and also successfully constructing some of the Country’s top golf courses that have held tournaments designed by noted Architects. He has project managed over 200 golf course construction projects all over the United States including working with more than 20 different Municipalities.  While in college, Doug also performed a special case study for the USDA on the Effects of Acid Rain on Forest Soils along with advanced studies in Business Management.


Juan Barba

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.


Kristen Battafarano

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.