ATLANTA, Ga. — The International Society of Arboriculture (ISA) is pleased to announce its renewed commitment to the Council of Tree and Landscape Appraisers (CTLA) and its collaboration on development of an eleventh edition of the Guide for Plant Appraisal.

Founded in 1975 and reaffirmed periodically, the CTLA is a collaboration of organizations that share an interest in developing industry consensus methodologies for tree and landscape plant valuation as published in the Guide for Plant Appraisal editions. First published in 1957 under the title Shade Tree Evaluation, the Guide for Plant Appraisal is the most informative and comprehensive reference on current knowledge of the approaches, processes, and methods of amenity plant valuation.

The seven organizations that make up the CTLA—AmericanHort, American Society of Consulting Arborists, American Society of Landscape Architects, National Association of Landscape Professionals, Association of Consulting Foresters of America, the International Society of Arboriculture, and the Tree Care Industry Association—reaffirmed their working contract in November 2023 to carry their collaboration forward with a new edition of the Guide.

“We are excited to see the historic collaboration of the Council of Tree and Landscape Appraisers being reaffirmed so that we can ensure the Guide for Plant Appraisal is kept current and relevant for the industry,” said Caitlyn Pollihan, CEO & Executive Director of the International Society of Arboriculture, the organization that publishes the Guide.

With its renewed mandate, the CTLA has outlined a timeline for development of the eleventh edition of the Guide for Plant Appraisal. The revision process is set to begin in January 2024 with a yearlong public comment period to collect feedback on the current, tenth edition, of the Guide. In 2025, the CTLA’s Content Review Committee will assess all public comments and outline a direction for the revision.

A draft eleventh edition could be expected as soon as 2027, and will itself be subject to a public comment period prior to any publication. This aims to ensure openness for all parties who are directly and materially interested in providing input on the Guide. The Content Review Committee will again assess the comments and revise the draft as appropriate. The eleventh edition of the Guide for Plant Appraisal could be published as soon as 2029.

The current edition of the Guide for Plant Appraisal is available in digital and print format through ISA’s online web store. Inquiries regarding the Guide for Plant Appraisal or the Council of Tree and Landscape Appraisers can be directed to eps@isa-arbor.com.

ABOUT ISA
The International Society of Arboriculture (ISA), headquartered in Atlanta, Ga., U.S., is a nonprofit professional organization dedicated to promoting the importance of arboriculture and educating the public about the significance of trees and the value of their proper care. As part of ISA’s advancing the arboriculture profession, it offers the only internationally‐recognized certification program in the industry, including ISA Certified Arborist ®.