Tree Appraisal

Note: The American Society of Consulting Arborists (ASCA) is asking for participation in an industry survey critical to the profession of Tree and Plant Appraisers. The goal of the survey is to determine the essential knowledge areas required by today’s tree and plant appraisers in order to update the current certificate program for this field: ASCA’s Tree and Plant Appraisal Qualification (TPAQ). It is important that those of you who perform tree and plant appraisals share your input as key stakeholders of this training and education program. The survey will take the 10-15 minutes and participants will be entered to win one of two $100 Amazon gift cards! Responses must be submitted by July 31, 2022. Find out more information and access the survey.

The Guide for Plant Appraisal, 10th Edition is the most informative and comprehensive alignment of current knowledge of the approaches, processes, and methods of plant valuation. This edition represents a systematic evolution of plant appraisal that integrates new research into a deeper understanding of the strengths and weaknesses of the available methods. Included in this edition are detailed discussions of newly streamlined core concepts and terminology, a review of the organization and context of appraisal reports, and an updated emphasis on appraiser awareness of the environmental and ecological benefits plants provide. Also new to this edition are appendices and a glossary. You can purchase this Guide here. 

Notice Regarding the Texas Supplement to the 10th Edition of the Guide for Plant Appraisal: 
The Texas RPAC has determined that 3” caliper (or #65 container), will remain the Largest Commonly Available size for calculating Unit Costs and other uses outlined in the 10th Edition of the Guide. Under guidelines set forth in the 10th Edition, when utilizing the Trunk Formula Technique, it is now recommended that unit costs be calculated for each separate species of tree being appraised.  Tree costs are widely available from nursery catalogs and internet-based websites (such as, and tree appraisers are encouraged to utilize these or similar tree pricing sources when determining unit costs for a particular appraisal assignment. If you have any questions or issues about the 10th Edition, please contact Micah Pace, Chair of the Texas RPAC at

(For those who choose to continue using the 9th Edition, unit costs are provided in the 2019 Texas Supplement for the 9th Edition of the Guide available here. The 2019 update is the last update for the Texas Supplement for the 9th Edition of the Guide and it will no longer be updated annually by the Texas Chapter. If you choose to continue using the 9th Edition of the Guide to Plant Appraisal and want to update the universal unit tree cost value (which is now required by species in the 10th) that was previously developed and updated by the RPAC, it should be adjusted for inflation using an online inflation calculator.  As professional arborists practicing appraisals, it is important to always feel comfortable with your methodology and have confidence that the chosen methodology can be defended and supported.)