Sonoma County treats native oaks and oak woodland as a protected resource, and in April 2024 the Board of Supervisors adopted the first major overhaul of the county's tree rules since 1989. If you own property in the unincorporated county — which includes most of the land around Cloverdale, Geyserville, and Healdsburg outside city limits — these rules apply to you. Here's the plain-language version.
The 2024 rules in unincorporated Sonoma County
- 31 native species are protected, including valley oak, coast live oak, black oak, blue oak, interior and canyon live oak, Oregon oak, madrone, big leaf maple, California black walnut, buckeye, redwood, and several pines and firs.
- The threshold is 6 inches in diameter at breast height (4.5 feet up the trunk). Removing a protected species at or above that size generally requires a permit under the Tree Protection Ordinance.
- Big trees need more. Hardwoods over 36 inches in diameter and redwoods over 48 inches require a use permit — a more involved process than the standard zoning permit.
- Fees and fines run $500 to $3,500 per tree depending on size, and mitigation replanting can reduce or avoid the fees.
- The Oak Woodland Combining District is a separate overlay: parcels that had at least half an acre of oak woodland as of 2013 fall under the Oak Woodland Ordinance, which allows a one-time conversion of up to half an acre but requires a use permit for larger projects.
- Eucalyptus is not protected under the tree ordinance (other rules like riparian corridor protections may still apply near creeks).
Inside city limits, different rulebook
| Jurisdiction | The gist |
|---|---|
| Unincorporated Sonoma County | 2024 ordinance: 31 protected native species at 6″ DBH; use permit above 36″ (48″ redwood); Oak Woodland overlay on mapped parcels. |
| Cloverdale (city limits) | City protected/heritage tree rules apply — check with the city's planning department before removing mature natives. |
| Healdsburg | City heritage and street tree rules; strict on heritage oaks. |
| Santa Rosa | City ordinance protects native species at a lower 4″ threshold; permits through the Planning Division. |
| Windsor | Native oaks are protected trees; removal requires a town permit. |
When you generally DON'T need a permit
- Dead, dying, or diseased trees — typically exempt, but document the condition (photos, an arborist note) before cutting.
- Genuine emergency hazards — immediate risk to life or property. Document before, notify after.
- Fire fuel management done in compliance with fire-safe standards is exempt in the county ordinance (with limits — redwoods excluded, minimum removal necessary).
- Non-protected species like eucalyptus — though location-based rules (riparian corridors, nesting season under the Migratory Bird Treaty Act) can still apply.
Even for exempt removals, the county recommends keeping receipts and photos in case of a code-enforcement question later. Cheap insurance.
The Mediterranean Oak Borer, plainly
MOB is an invasive ambrosia beetle killing oaks across Sonoma County — the Town of Windsor has been removing infested heritage oaks from its parks since 2023. What to look for: crown thinning that starts at the top, fine boring dust on the bark, tiny exit holes, and fast decline over one or two seasons — including oaks dropping still-green leaves in summer.
Two things matter practically. First, a MOB-killed oak usually qualifies under the dead/dying/diseased exemption — but photograph the decline before removal. Second, the wood must be handled so the beetle doesn't spread: chip it on site or leave it there. Don't move infested firewood off the property — that's how the beetle got here in the first place.
What this means in practice
Get an assessment before you cut, photograph everything, and if a permit applies, the paperwork is days-to-weeks, not months — far cheaper than a $3,500-per-tree fine for skipping it. Free assessments anywhere in northern Sonoma County; we'll tell you straight whether your tree needs paperwork or just a saw.
This guide summarizes county and city rules as of mid-2026 for general information; ordinances change and parcels differ. Verify current requirements with Permit Sonoma or your city planning department before removal.