Plants Expert Witnesses: 3

David D. Hunter is a Registered Consulting Arborist  with ASCA, USFS Trained Tree Risk Assessor, ISA Certified Arborist. ISA Tree Risk Assessor Qualified Professional Plan Appraiser and Professional Forester. Providing both Expert Witness and Consulting Services. David D. Hunter has been called upon to testify in court and has helped his clients reach resolution prior to trial. His services include: Expert Witness in Arboriculture and Forestry, professional plant appraisals of landscapes, trees and timber trespass, Tree Forensics as to why a tree or tree part failed causing injury or death, tree health and hazard/ risk assessments, and insurance claims relating to damage to tree, or people/property damaged by trees. David D. Hunter has over 40 years of experience from working in forestry, wildland fire and the field of arboriculture. David D. Hunter has been a consultant and expert witness in these fields for over 25 years. David D. Hunter services the western United States but is available nationwide.

Areas of Expertise:

• Arboricultural and Timber Trespass Issues
• Tree Forensics
• Tree Inventories
• Tree Surveys and Tree Protection Plans
• Tree Preservation Plans and Construction Sequences
• Hazard Tree Evaluations and Reports
• Appraisal of Loss Reports regarding Landscape Value Loss
• Arborist Reports

Training & Certifications:

• Certified as an Arborist PN-1068A, by the International Society of Arboriculture (ISA) - 1997-Present
• Graduate American Society of Consulting Arborists (ASCA), Arboriculture Consulting Academy
• Tree Failure Training Conference, Certified as Evaluator Portland, OR
• Registered Consulting Arborist membership in ASCA, RCA #408 (2003)
• US Forest Service Hazard Tree Risk Assessor Trained since 1979
• Certified Tree Risk Assessor (CTRA) by PNW ISA # PN-0150 (2006)ISA Tree Risk Assessor Qualified (2017)

View David Hunter's Consulting Profile.

Brian Zimmerman, PE, has over 35 years of experience in the Commercial HVAC Engineering and Design market. The past 13 years, Mr. Zimmerman has designed over 350 Cannabis Cultivation and Processing Facilities across the US and Canada. 

Mr. Zimmerman is an expert in sizing and specifying HVAC equipment in the indoor cannabis and controlled environmental agriculture (CEA) markets. His specialty is in HVAC equipment sizing, control, and capabilities for maintaining stable design setpoints for temperature and relative humidity (RH).

Litigation Support - A Registered Professional Engineer in Colorado, Arizona, and California, Mr. Zimmerman provides expert witness services to attorneys representing plaintiff and defendant. Cases include issues with cannabis cultivation and other indoor agriculture facilities. Services include on-site inspection, thorough reporting, depositions, and trial testimony as needed.

Areas of Expertise:

Background Experience - Mr. Zimmerman served as the Executive Vice President of Engineering at Urban-Gro, Inc. from 2019 through August 2022. He was previously the President and Owner of Impact Engineering, Inc., a company acquired by Urban-Gro in March 2019. Mr. Zimmerman founded this company in 1997 to provide full-service HVAC, plumbing, and electrical engineering, and consulting for the cannabis commercial development industry. 

In 2009, Mr. Zimmerman and his team at Impact Engineering designed the first cultivation facility in Colorado for Medicine Man Technologies. Since then, Impact Engineering has designed over 350 cannabis cultivation facilities across the US and in Canada. Mr. Zimmerman has perfected the ability to size and control the indoor environment with mechanical equipment to maximize the quantity, quality, health and consistency of product from harvest-to-harvest.

View Brian Zimmerman's Business Consulting Profile.

John A. Harris, Principal of Landscape Economics, LLC, and President of Earth Advisors, Inc., is a LANDSCAPE ECONOMIST who has worked in the Arboriculture, Forestry, landscape and horticultural fields for over 20 years. Mr. Harris has provided reputable consulting, education and project management services for a wide variety of projects across the United States and internationally, in both temperate and tropical ecosystems. Areas of Expertise:

• Arboriculture, Landscape, Plant Nursery, Industry Standards and Practices
• Landscape and Tree Risk Assessments
• Landscape and Tree Value Appraisals
• Landscape and Tree Damage Appraisals
• Storm Damage Assessments, Claims, and Recovery

• Arboriculture Industry Standards and Practices
• Landscape, Arboriculture, Forestry, Environmental Project Management
• Utility Line Clearance Industry Standards and Practices
• Landscape Industry Standards and Practices for design, installation, maintenance
• Personal Injury and Wrongful Death involving tree or landscape issues
• Municipal Tree Inventory and Management Plans
• Duty of Care and Negligence in Tree and Landscape Maintenance
• Forestry and Forest Resources Management
• Grounds Maintenance Practices
• Arboriculture and Arborist Practices