Tree-board discussion turns to proposed changes to exceptional-tree sizes and code language

The Lake Forest Park Tree Board spent substantial time Thursday reviewing proposed amendments to the city's exceptional-tree code and related code housekeeping items, including revising size thresholds for specific native species and clarifying which tree list the code references.

Why it matters: Proposed changes to the exceptional-tree thresholds would change the diameter-at-breast-height (DBH) thresholds at which specified species receive extra protections. Those thresholds determine when tree removal triggers additional review or replacement obligations and can affect private-property decisions, development reviews and mitigation requirements.

Board discussion: City staff presented draft thresholds developed from a recent sample inventory and previous practice and sought guidance on how to justify the proposed numbers in any ordinance. Members and staff agreed that each numeric threshold must have a documented justification (for example, growth expectations, 50- to 100-year size projections, or I-Tree-derived benefits such as carbon sequestration and pollution removal) because legal review will require a defensible basis for the chosen cutoffs. Board members recommended adding language to the memorandum and ordinance record that explains the analytic basis (inventory data, I-Tree outputs and comparison to other municipal codes), and suggested marking small-sample results with an asterisk or "sample-size too small" note rather than presenting potentially misleading percentages.

Scope and technical issues: Staff said some species show low counts in the city's inventory sample, which makes percentage estimates unreliable for those species. The board discussed options: (1) retain the prior thresholds where no defensible new basis exists; (2) remove species-specific rows that lack robust justification and keep them in a catch-all category; or (3) use a growth-based formula (for example, a percentage of the expected mature diameter at a given age) so thresholds follow a reproducible method rather than a single expert judgment.

Process and timing: Staff warned the board that code amendments will require legal review and an ordinance process (including SEPA notice as appropriate) before council adoption. Board members asked staff to gather previous ordinance records (the meeting referenced ordinances 1152 and 1157 from 2017 as the origin of current code language), assemble the scientific justification for each recommended number (I-Tree metrics and growth estimates), and return to the board with a revised memo. The board and staff said it may be preferable to combine a set of housekeeping code cleanups (tree list reference, clarity changes) in a single package to minimize repeated SEPA and ordinance processes.

What was decided: The board did not vote on code amendments at this meeting. Members directed staff to refine the recommended thresholds, attach supporting data and draft an ordinance recital that documents the justification for each threshold. Staff indicated legal review is required and that a non-project SEPA review could take multiple weeks unless expedited review is granted.

Ending: Staff agreed to return with written justification for each proposed threshold, sample-size flags where appropriate, and a recommended ordinance package for board review prior to legal submittal and council hearings.