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ASCA On Demand

ASCA, the industry's professional association that focuses solely on arboricultural consulting, is offering a four-part tree appraisal webinar series.

The American Society of Consulting Arborists is now offering a 4-part webinar series on tree appraisal. The online courses will explore technical aspects of replacement cost and trunk formula methods--size, species, condition, and location--providing tools to perform any appraisal with confidence.

Session One - Overview & The Basics
This session introduces the webinar series, plant appraisal, and the cost approach. It describes the trunk formula and replacement cost methods, the factors important in their use, and the techniques employed for establishing unit cost and basic price. The session discusses the importance of Regional Appraisal Committees and introduces the basics of data collection and field procedures.

Session Two - Assessing Size & Species
This session is an in depth exploration of the Size and Species factors. For Size, it reviews the location and approach to measuring trunk diameter, as well as the variations commonly encountered in the field. It reviews the key elements used in establishing the Species factor and the regional variation that occurs. The session describes use of Regional Species Ratings.

Session Three - Assessing Condition & Location
This session explores the Condition and Location factors. It reviews common methods used in assessing tree health and structure, and the treatment of correctable problems. The elements used in establishing the Location, site, contribution and placement, are introduced and discussed. A conceptual approach to establishing Location ratings is provided.

Session Four - Summary & the Future
The final session in this four-part series looks at the current status of the 10th Edition of the Guide for Plant Appraisal. This session reviews the important technical issues that need to be addressed when using the Cost Approach and how those elements may change with the 10th Edition. The session discusses how the iTree software suite employs Cost Methods as well as its use of the Market Approach to establishing tree value.

About the Presenters
Dr. James Clark is vice president of HortScience, Inc. and is an internationally renowned arborist. He has twenty years of technical, research, and practical experience in tree risk assessment, tree preservation, and urban forest planning and management.

He holds a B.S. in Plant Science and an M.S. in Horticulture from Rutgers University, and a Ph.D. in Plant Physiology from the University of California, Davis, is a Certified Arborist (WE-0846), and a Registered Consulting Arborist (ASCA #357). Jim's first workshop in tree appraisal was in 1980. Since then he has undertaken a wide range of appraisal assignments and provided expert testimony involving tree appraisal. He has lectured and conducted training workshops on tree appraisal methods.

Brian Gilles is an active consulting arborist providing a broad range of services to clients. He founded and still owns his own firm, Gilles consulting, 20 years ago. Before he began his career in arboriculture, Brain worked in the field of park operations management. Prior to his work in park management, he proudly served in the United States Air Force. Brian is received a B.S. in Wildland Recreation Management from the University of Idaho, is a Registered Consulting Arborist (ASCA #418), is a Certified Arborist & Certified Tree Risk Assessor with ISA.

Lisa Hammer is a native Miamian. She attended the University of Florida, where she graduated in 1981 with a B.S. degree in Agriculture. She majored in Fruit Crops, and earned a Certificate of Specialization in Tropical Agriculture. Her goal was to work in developing tropical countries promoting sustainable agriculture, so she enrolled in the Master's program in Tropical Agriculture at the University of Hawaii. A year later she returned to Florida and accepted a UF faculty position as a Cooperative Extension Agent for "Urban Horticulture" in the Miami area. While working full-time, she attended graduate school at Florida International University and in 1987 graduated with an M.S. degree in Biology.

For more information about ASCA or webinars, please visit

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November 22, 2019, 12:47 pm PDT

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