Arborist letters, ISA guidance and enforcement: city arborist urges education over immediate enforcement

City Arborist Chris Delk told the Environmental Stewardship Committee that some private "arborist letters" show signs of bias or are incomplete and that the profession’s updated ISA guidance (third edition) strengthens ethical expectations for assessments. "If your intent is to deceive before you make the assessment, you're already in ethics violation," Delk said, describing how the new guidance clarifies responsibility and how staff can respond to dubious letters.

Delk described the trade-off between policing potentially fraudulent letters and preserving a cooperative relationship with local working arborists. "If I make all the arborists really mad at us, we're not gonna have anybody cut down [or] prune our trees," he said, noting that investigations and formal ethics complaints require significant staff time. The committee agreed staff should continue to push for higher-quality letters, add friction to the permitting process when appropriate, and use the arborist office and education to reduce poor-quality submissions.