Do I Need a Tree Permit in Hillsborough?
Hillsborough updated its tree protection ordinance in March 2023 with stricter rules. All trees 18 inches diameter or more are now protected — regardless of species. Heritage trees at 50 inches circumference face the toughest scrutiny. Here's how the new rules work.
Does my tree need a permit?
Select your tree type and measure the trunk to get an instant answer based on Hillsborough's ordinance (Tree Protection Ordinance (2023)).
DBH = diameter measured at 4 feet 6 inches above grade. Wrap a tape around the trunk and divide by 3.14.
What trees are protected in Hillsborough?
Hillsborough's March 2023 ordinance update applies a single diameter threshold (18 inches) across all species — no species-specific thresholds. Heritage trees are defined at 50 inches circumference. The penalty formula of $150 per inch of trunk diameter makes large-tree violations extremely expensive. Pruning beyond 25% of canopy also requires a permit.
| Category | Protected at | Notes | Penalty |
|---|---|---|---|
| All species — protected | ≥18″ diameter | At 4′6″ above grade (2023 ordinance) | $150/inch or appraised value |
| Heritage trees | ≥50″ circumference | Highest protection level | $150/inch + appraised value |
| Street trees | Any size | Town-owned, in right-of-way | Town replacement + penalties |
Not sure if your tree qualifies?
Measure first. An arborist consultation ($150–$300) is far cheaper than violation penalties. Call Building & Planning at (650) 375-7411 — they can often tell you on the phone whether your tree is likely protected.
How to get a tree removal permit in Hillsborough
Hillsborough's permit process runs through Building & Planning. Here's the step-by-step sequence:
Measure your tree
Measure trunk diameter at 4 feet 6 inches above grade. If 18 inches or more (any species), the tree is protected. Heritage trees start at 50 inches circumference.
Hire a certified arborist
An ISA Certified Arborist report is required. The report must document condition, reason for removal, and alternatives. Budget $300–$600. Hillsborough estate trees often require more detailed assessments.
Submit to Building & Planning
File the application with Building & Planning at (650) 375-7411. Include the arborist report, site plan, and photos. Pay the permit fee (approximately $150).
Town review
A town arborist reviews the application. Heritage trees may require additional review. Processing time varies — Hillsborough's estate properties often involve complex tree situations.
Receive permit and schedule work
Once approved, hire a licensed tree service (CSLB C-61/D-49). Replacement planting may be required. The permit must be on-site during removal.
What happens if you remove a tree without a permit?
$150 per inch of trunk diameter — or full appraised value
Hillsborough calculates penalties at $150 per inch of trunk diameter or the full appraised value of the tree, whichever is greater. For a heritage oak with a 30-inch trunk, that's $4,500 minimum in per-inch fines alone — before appraised value is considered. Heritage oaks on Hillsborough estates can appraise at $50,000–$150,000+.
A permit costs approximately $150 and takes Varies. The penalties for skipping it are orders of magnitude higher. There's no scenario where unpermitted removal saves money.
Hillsborough Building & Planning — contact and resources
Call before you apply
Building & Planning staff at (650) 375-7411 can often tell you whether your tree is likely protected before you spend money on an arborist report. Worth a 10-minute call.
Frequently asked questions
Does pruning require a permit in Hillsborough?
Pruning up to 25% of a protected tree's canopy does not require a permit if it follows ISA standards. Pruning beyond 25% requires a permit. Structural pruning on heritage trees should always involve an ISA Certified Arborist.
What if the tree is dead or hazardous?
Dead or imminently hazardous trees may qualify for expedited removal, but you still need to contact Building & Planning before proceeding. Document the hazard with photos. Emergency removals must be reported promptly.
What changed in the 2023 ordinance update?
The March 2023 update simplified Hillsborough's tree protection by applying one 18-inch diameter threshold across all species (previously thresholds varied). It also strengthened heritage tree protections at 50 inches circumference and clarified the penalty formula of $150 per inch of trunk diameter.
Related reading for Hillsborough tree owners
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