Why Napa Valley Cities Are Increasingly Strict About Permits for Tree Removal
Why Tree Removal Safety Matters More Than It Appears
In April 2024, the Sonoma County Board of Supervisors adopted two tree protection ordinances, the first update to the county's tree protection law since 1989. The changes were three years in the making, involved multiple rounds of public hearings and stakeholder feedback, and produced a regulatory framework that is significantly more protective of native trees on Sonoma County properties than anything that existed before.
For property owners in Glen Ellen, Kenwood, and the unincorporated communities of the Sonoma Valley, the 2024 ordinance update changed the permit requirements, the fee structure, and the compliance obligations for tree removal in ways that many homeowners have not yet fully understood. Removing a protected native tree without the required permit is not a gray area. According to Local News Matters reporting on the April 2024 adoption, fees for removing protected trees increased to a maximum of $3,500 per tree under the new law.
For property owners in Napa County and the city of Sonoma, separate municipal codes apply with their own requirements and thresholds. The regulatory picture across the Napa Valley and Sonoma County region is not uniform, which is one of the reasons that understanding which rules apply to a specific property before any tree work begins is not optional.
This article covers what the current permit requirements look like across the region, why the regulatory environment has tightened, which trees are protected and which are not, and why working with an ISA Certified Arborist who knows these regulations is the practical answer to navigating them correctly.
What the 2024 Sonoma County Ordinance Update Actually Changed
The April 2024 ordinances adopted by the Sonoma County Board of Supervisors created two distinct regulatory instruments that apply to different situations on unincorporated Sonoma County properties.
The Tree Protection Ordinance (Code Section 26-88-010(m))
According to Permit Sonoma's official published requirements, the Tree Protection Ordinance requires a zoning permit and mitigation when removing certain tree species above 6 inches diameter at breast height. A use permit is required for certain large trees exceeding specific thresholds.
The specific requirements under the updated ordinance are:
Zoning permit required: For the removal of any protected native species at or above 6 inches diameter at breast height (DBH), measured at 4.5 feet from the ground
Use permit required: For the removal of protected hardwoods at or above 36 inches DBH, or redwoods at or above 48 inches DBH
Mitigation required: Removal of protected trees requires mitigation in the form of replanting, preservation of other trees, or payment of in-lieu fees
Maximum violation fee: $3,500 per protected tree removed without the required permit, according to Local News Matters' reporting on the April 2024 adoption
The 31 protected species under the Sonoma County Tree Protection Ordinance:
According to Local News Matters' verified reporting on the ordinance adoption, the 31 protected species include big leaf maple, black oak, blue oak, boxelder, California black walnut, California buckeye, canyon live oak, coast live oak, two cottonwood species, interior live oak, madrone, Oregon ash, Oregon oak, red and white alder, valley oak, two willow species, two cypress species, grand fir, and additional species including redwood. This list covers the vast majority of mature native trees found on residential and rural properties throughout the Sonoma Valley, Glen Ellen, and Kenwood.
The Oak Woodland Ordinance (Code Section 26-67)
The second ordinance adopted in April 2024 addresses tree removal and development within Oak Woodlands on parcels located in the OAK Combining Zone. According to Permit Sonoma's official guidance, the Oak Woodland Combining Zone applies to any parcel that contained at least half an acre of woodlands as of 2013, even if trees have since been removed or were burned as a result of wildfire.
On parcels with this zoning designation, the ordinance allows a one-time exception per parcel for up to half an acre of woodland removal subject to a zoning permit. Beyond this exception, development in an Oak Woodland, including new structures, new cultivation areas, or other land use that will result in the permanent loss of Oak Woodlands, requires a use permit.
The Valley Oak Habitat Combining Zone
A separate Valley Oak Habitat Combining Zone also applies to certain Sonoma County properties, requiring a zoning permit and mitigation for the removal of valley oak trees within the specified zoning district. Valley oak is one of the most commonly encountered trees on Sonoma Valley residential properties and ranch land in the Glen Ellen and Kenwood areas.
Why the Regulatory Environment Tightened: The Three Drivers
Understanding why Sonoma County updated its tree protection framework in 2024 helps property owners understand the direction the regulatory environment is moving, not just where it currently stands.
Climate resilience and carbon sequestration
According to Local News Matters' reporting on the ordinance adoption, the new law is meant to increase climate resiliency by enhancing carbon sequestration and bring fees up to date to mitigate losses. Mature native trees, particularly the valley oaks, coast live oaks, and redwoods that define the Sonoma County landscape, are among the most carbon-dense biological systems in California. Their removal represents a measurable loss of carbon sequestration capacity that the county's General Plan calls for protecting.
The wildfire context
The fires that burned through Sonoma County in 2017, 2019, and 2020 removed significant tree canopy across large areas and created a heightened awareness of tree loss at the landscape scale. The 2024 ordinances were developed in a planning environment where tree canopy loss was not an abstraction but a documented recent reality. The Oak Woodland Combining Zone's application to any parcel that contained woodland as of 2013, regardless of whether those trees are still standing after fire, reflects this context directly.
The 35-year gap in regulatory updates
The previous Sonoma County tree protection law dated to 1989. The landscape of property development, subdivision activity, vineyard expansion, and residential construction in the Sonoma Valley in the intervening 35 years created conditions where tree removal was occurring at a pace and scale that the 1989 framework was not designed to manage. The 2024 update brought the regulatory framework into alignment with the current conditions on the ground.
How This Applies to Properties in Glen Ellen, Kenwood, and the Sonoma Valley
Glen Ellen and Kenwood are unincorporated communities in the Sonoma Valley, which means they fall under Sonoma County's jurisdiction rather than under the municipal code of the city of Sonoma. The 2024 Tree Protection Ordinance and Oak Woodland Ordinance apply to properties in these communities.
For property owners in Glen Ellen and Kenwood, the practical implications are significant:
Most mature native trees require a permit before removal
The 6-inch DBH threshold that triggers the zoning permit requirement under the Tree Protection Ordinance is a relatively modest size. A valley oak, coast live oak, madrone, or big leaf maple at 6 inches DBH is a tree that has been in the ground for years and is a visible, established presence on the property. The vast majority of mature native trees that property owners in the Sonoma Valley might consider removing for any reason, including hazard, construction clearance, view enhancement, or agricultural use, fall above this threshold and require a permit.
Oak woodland parcels have additional requirements
The OAK Combining Zone applies to any parcel that contained at least half an acre of woodlands as of 2013. Many residential parcels, ranch properties, and rural lots in Glen Ellen and Kenwood meet this threshold. Property owners should verify their zoning designation through Permit Sonoma's property search tool before undertaking any tree removal that involves oak trees.
Riparian corridor properties face additional restrictions
Properties near streams, creeks, and drainages in the Sonoma Valley are subject to the Riparian Corridor Combining Zone, which prohibits vegetation removal, grading, and structures within designated stream channels and streamside areas. Glen Ellen's proximity to Sonoma Creek and the multiple tributaries that flow through the valley means that riparian corridor restrictions apply to a meaningful portion of the area's properties.
What the City of Sonoma's Municipal Code Requires
The city of Sonoma operates under its own municipal tree ordinance, separate from the county's framework. According to the Sonoma Municipal Code, Chapter 12.08, the city maintains its own tree protection provisions that apply within city limits. Property owners in the incorporated city of Sonoma should verify requirements directly with the city's planning department rather than assuming that county requirements apply.
What Napa County Requires for Tree Removal
Napa County and the city of Napa maintain separate tree protection requirements from Sonoma County. Property owners in Napa Valley should not assume that Sonoma County's 2024 ordinance updates apply to their properties. The regulatory framework in Napa County has its own protected species list, permit thresholds, and application process through the Napa County Planning, Building and Environmental Services department.
For properties in the unincorporated areas of Napa County, including rural properties in the Napa Valley wine country corridor, tree removal involving certain protected species and sizes requires a permit through the county. The specific requirements vary by zoning designation, tree species, and diameter, and should be confirmed with Napa County Planning staff before any removal work is undertaken.
The Practical Consequence: What Happens When a Permit Is Not Obtained
The enforcement consequences of removing a protected tree without the required permit in Sonoma County are specific and significant. The $3,500 per tree maximum violation fee documented in the April 2024 ordinance adoption is the financial penalty dimension. But the regulatory consequences extend beyond the fine.
What unpermitted tree removal can trigger:
Stop work orders: If unpermitted tree removal is discovered during or after construction or development activity, a stop work order can halt the entire project until compliance is addressed
Mitigation obligations: Even after a violation, the mitigation requirements that would have applied to a permitted removal still apply. The property owner may owe replanting obligations or in-lieu fees in addition to the violation penalty
Permit complications for future projects: A record of code violations on a property can complicate future permit applications for any development, construction, or land use change on that parcel
Neighbor and public complaints: In communities like Glen Ellen and Kenwood where land use and environmental stewardship are closely watched by engaged residents, unpermitted tree removal is the type of activity that generates complaints to the county that trigger enforcement
The permit process, while it requires time and documentation, is not designed to prevent all tree removal. It is designed to ensure that removal of protected trees is evaluated, mitigated, and documented. A property owner with a legitimate reason to remove a protected tree, whether hazard, construction necessity, or agricultural use, has a pathway through the permit process. Proceeding without the permit forecloses that pathway and creates the liability described above.
Why Working With a Certified Arborist Simplifies the Permit Process
The permit application for tree removal in Sonoma County requires documentation of the tree's species, diameter, condition, and the reason for removal. For hazard tree removals, the application is strengthened by a professional arborist's assessment that documents the structural defects or conditions that create the hazard, providing the county with the technical basis for permit approval.
Mike's Tree Service provides ISA Certified Arborist assessments throughout Sonoma County and Napa Valley, including Glen Ellen, Kenwood, Sonoma, and the surrounding communities. For properties in the OAK Combining Zone, the Valley Oak Habitat Zone, or near riparian corridors, the assessment includes identification of which regulatory framework applies and what the permit requirements are before any removal recommendation is made.
What the assessment covers for permit-related removals:
Species identification and diameter measurement: Confirming whether the tree meets the thresholds that trigger permit requirements under the applicable ordinance
Zoning designation verification: Identifying whether the property falls within the OAK Combining Zone, the Valley Oak Habitat Zone, the Riparian Corridor Combining Zone, or other overlays that affect the permit requirements
Condition documentation: For hazard removals, providing the written arborist assessment of structural defects, decay indicators, and risk factors that supports the permit application
Mitigation options: Identifying the replanting or preservation options that satisfy the mitigation requirements of the applicable ordinance
Navigating the permit requirements for tree removal in Sonoma County and Napa Valley is more manageable when the arborist conducting the removal assessment understands the regulatory framework as well as the tree biology. Mike's Tree Service has been working on properties throughout this region long enough to know which ordinances apply where, what the permit process requires, and how to document a removal in a way that supports a straightforward permit approval rather than a complicated one.
