Whatcom County, WA Landscaping Rules: Tree Removal & Heritage Trees (2026)

430 requires a permit before removing any significant tree on property within the Lake Whatcom watershed that is not tied to an active development proposal. Two removals are exempt outright: hazard trees that pose an emergency, provided the owner submits photo documentation to the county within 30 days of abatement, and pruning or maintenance that removes up to 25 percent of a tree's foliage. 16 (Critical Areas), and the stricter rule controls where the two overlap. Applications must include a sketch locating significant trees proposed for removal, species and canopy-area calculations, the location of structures and easements, and, for required replacements, a planting plan.

The director reviews a completed application within 21 calendar days, may approve it outright, approve with conditions, deny it, or request more information, and approved removal must be completed within one year. With a valid permit, an owner may remove up to 20 percent of existing significant-tree canopy, capped at 14,000 square feet measured cumulatively from January 1, 2017, so long as no development application is pending and no prior condition of approval requires the tree's retention. The director can allow additional canopy removal case by case for Firewise fire-risk reduction recommended by a certified professional or for pest and disease control prescribed by an ISA-certified arborist.

Hazard trees beyond the standard allowance require a tree risk assessment by a qualified professional, and each one removed must be replaced with three native trees. 94 WCC, with replacement conifers at least eight feet tall and replacement deciduous stock at least two and one-half inches in diameter. 160.