Coast Live Oak
The coast live oak is the most important tree species on the SF Peninsula — and the one most likely to get you in trouble with city hall. Protected in every Peninsula city, these long-lived evergreen oaks define the region's character and are the species most commonly involved in permit disputes, construction conflicts, and Sudden Oak Death.
How to Identify Coast Live Oak
- Leaves are small (1–3 inches), oval, with spiny or smooth edges — often both on the same tree
- Leaves are dark green and convex (cupped) on top, paler underneath
- Bark is smooth and gray on young trees, becoming deeply furrowed and dark with age
- Acorns are slender and pointed, 1–1.5 inches long, maturing in one season
- Growth habit is broadly spreading with a rounded or irregular crown
- Often multi-trunked, especially in open settings
Where It Grows on the Peninsula
Abundant throughout — found in every Peninsula city from San Francisco to Menlo Park. Dominant in Atherton estates, Palo Alto's hillside open spaces, and Burlingame's hillside neighborhoods. Less common in fill soils near the Bay.
Protection Status by City
Is your coast live oak protected? Here's the status in each Bay Area city we cover. Notable: Mountain View protects oaks at just 4" diameter and Campbell at 6" (see our interactive map for a visual overview):
| City | Status | Threshold | Notes |
|---|---|---|---|
| Palo Alto | ✓ Protected | 57″ circumference | Protected as a native species regardless of heritage tree status |
| San Mateo | ✓ Protected | 56″ circumference | Protected under the all-species ordinance |
| Redwood City | ✓ Protected | 48″ circumference | Heritage tree program |
| Menlo Park | ✓ Protected | 31.4″ circumference | Lowest threshold on the Peninsula — oaks get special protection. Approved arborist list required. |
| Burlingame | ✓ Protected | 44″ circumference | Protected; 25% annual pruning limit applies |
| Atherton | ✓ Protected | All sizes in setback areas | Native oaks protected regardless of size near property lines |
| Berkeley | ⚠ Moratorium | 18″ circumference (~5.7″ DBH) | Indefinite removal moratorium (BMC 6.52). Only species-specific protection in Berkeley. Removal allowed only if tree poses danger to life/limb. 25% pruning limit per 24 months. |
| Oakland | ✓ Protected | 4″ DBH | Lowest oak threshold in the Bay Area (OMC 12.36). Coast live oaks become protected within a few years of planting. $915K fine precedent for unauthorized removal. |
| Piedmont | ✗ No ordinance | — | Piedmont has no tree protection ordinance. No permit required for removal on private property. |
Need to check if your specific tree needs a permit? Use our permit checker .
City permit guides
Oaks are protected in most Bay Area cities, but thresholds vary widely
Common Issues & Diseases
Coast live oaks are canker hosts for Phytophthora ramorum — the disease causes bleeding trunk cankers and is often fatal. This is the #1 threat to Peninsula oaks. Learn more →
Armillaria mellea attacks roots, especially in trees stressed by overwatering or soil compaction. White fungal mats under bark near the base are diagnostic.
Secondary pest that attacks trees already weakened by SOD or drought. Tiny shot-holes in bark with fine sawdust are the signature.
The most common homeowner mistake. Coast live oaks evolved with dry summers — irrigation within the drip line promotes root rot and crown decline. Keep sprinklers away from the trunk.
Peninsula Care Calendar
Season-by-season care guidance for coast live oak on the SF Peninsula:
Best pruning window — oak bark beetles are dormant. Schedule structural pruning. Inspect for SOD cankers.
New growth flush. DO NOT prune — fresh wounds attract bark beetles during their active season. Monitor for sudden branch drop.
No irrigation within drip line. Watch for signs of drought stress vs. SOD (drought = uniform yellowing; SOD = bleeding cankers). Avoid any soil disturbance in root zone.
Acorn drop. Second pruning window opens late fall. Schedule arborist inspections before winter rains. Good time for SOD testing.
Detailed Notes
Fire Risk
Moderate — less flammable than eucalyptus or pine but can carry fire in extreme conditions. Dead wood in canopy increases risk.
Drought Tolerance
Excellent once established — evolved with California's dry summers. Overwatering is more dangerous than underwatering for mature trees.
Wildlife Value
Critical habitat provider — acorns feed deer, squirrels, scrub jays, woodpeckers. Cavities support owls, bats, and nesting birds. Supports 500+ insect species.
Arborist Pro Tips
Where to Find Coast Live Oak on the Peninsula
Find ISA-certified arborists experienced with coast live oak in these cities:
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Written by Michael Schuck, ISA Certified Arborist WE-15750A · Updated February 2026
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