Do I Need a Tree Permit in Hillsborough?
Hillsborough's tree protection ordinance (HMC Title 14, Ch. 14.04, Ord. 789, eff. 7/1/2023) protects any tree with a cumulative trunk diameter of 18 inches or more at 4'6" above grade — regardless of species. Multi-trunk trees are measured by adding all trunk diameters together. Here's how the rules work.
Does my tree need a permit?
Measure the trunk to get an instant answer based on Hillsborough's ordinance (HMC 14.04, Ord. 789). For multi-trunk trees, add all trunk diameters together.
Measure trunk diameter at 4 feet 6 inches above grade. For multi-trunk trees, add all trunk diameters together. If the total is 18 inches or more, the tree is protected.
What trees are protected in Hillsborough?
Hillsborough's ordinance (HMC Title 14, Ch. 14.04, Ord. 789, eff. 7/1/2023) applies a single threshold: 18 inches cumulative diameter at 4'6" above grade, across all species. Multi-trunk trees are measured by adding all trunk diameters together. There is no native/non-native split and no separate heritage tier. The penalty formula of $150 per inch of trunk diameter (or ISA-appraised value, whichever is greater) makes violations extremely expensive. Pruning beyond 25% of canopy also requires a permit.
| Category | Protected at | Notes | Penalty |
|---|---|---|---|
| All species (single threshold) | ≥18″ cumulative diameter | At 4'6" above grade; multi-trunk = sum of all diameters (Ord. 789) | $150/inch or appraised value + misdemeanor + 36"-box replacement |
| 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. Multi-trunk trees are measured by adding all trunk diameters together.
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 planning review fee ($1,076 FY 26-27).
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-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 — or ISA-appraised value, whichever greater
Hillsborough calculates penalties at $150 per inch of trunk diameter OR ISA-appraised value, whichever is greater, plus misdemeanor charges. A 30-inch tree carries a minimum $4,500 fine before appraised value. Violators must also plant a 36-inch-box replacement tree within 6 months (14.04.060). There is a 30-day hazard-removal window for approved hazard removals (14.04.040(E)), but no remove-then-notify option.
A permit costs $1,076+ (planning review, FY 26-27). 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?
Hazardous trees are reviewed by a town-qualified arborist. There is a 30-day hazard-removal window once approved (14.04.040(E)), but no remove-then-notify option. Dead tree permits cost $287. Document the situation with photos and an arborist report, and contact Building & Planning at (650) 375-7411 before any work.
What changed in the 2023 ordinance update?
Ord. 789 (eff. 7/1/2023) established a single category of 'Protected Tree': any species at 18 inches or more cumulative diameter at 4'6" above grade. Multi-trunk trees are measured by adding all trunk diameters. There is no separate native or heritage tier. The penalty formula is $150 per inch of trunk diameter or ISA-appraised value, whichever is greater, plus mandatory 36-inch-box replacement within 6 months.
Related reading for Hillsborough tree owners
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