Oak trees and gates in Santa Clarita
Where a gate post can go when there is an oak nearby.
Santa Clarita's oak ordinance, section 17.51.040, counts a post hole, a slide gate's track or an opener's power trench as work in the tree's protected zone when it lands there. Here is how that zone is drawn and which part of it needs a permit.
How the protected zone is drawn
Start at the dripline, the outer edge of the canopy. The protected zone begins 5 ft outside it and runs in to the trunk, and it is never less than 15 ft from the trunk (17.51.040(A)(2)(i)).
On a lot with a single family house, the code splits that zone in two. Work in the inner half, from the trunk out to half the zone's diameter, is a major encroachment and needs an oak tree permit. Work in the outer half is a minor encroachment, and minor encroachments are on the exemption list (17.51.040(A)(2)(f) and (B)(2)(i)).
The math on a few canopy sizes
Measure from the trunk to the dripline, add 5 ft, and use 15 ft if the result is smaller. Half of that radius is where the permit line falls.
| Trunk to dripline | Protected zone reaches | Permit needed inside |
|---|---|---|
| 5 ft | 15 ft (the minimum) | 7 1/2 ft of the trunk |
| 10 ft | 15 ft (the minimum) | 7 1/2 ft of the trunk |
| 15 ft | 20 ft | 10 ft of the trunk |
| 20 ft | 25 ft | 12 1/2 ft of the trunk |
| 30 ft | 35 ft | 17 1/2 ft of the trunk |
Figures worked from 17.51.040(A)(2)(i) and (f) for a single family lot. Canopies are rarely round, so measure the side the gate is on.
Which trees and which work count
Any oak of the genus Quercus counts, whatever its size. On a single family lot, scrub oak is left out, and no permit is needed for a tree 12 1/2 in or less around the trunk at 4 1/2 ft above grade (17.51.040(A)(2)(a) and (B)(2)(a)). An oak of 108 in or more around is a heritage oak.
For a gate, the work that counts is broad. The code lists trenching, excavating and paving inside the zone as damage, and its list of encroachments adds grading, building structures and even storing materials or equipment. Cutting includes roots, so a root in the way of a post hole is part of the tree.
When the gate does need a permit
The oak tree permit is issued under 17.23.170. The application calls for an oak tree report, a survey of the tree with its dripline and protected zone, drawings of the proposal and tree tags unless the Director waives them. The city can attach conditions, such as replacement trees or a care program.
Encroaching without one is a misdemeanor, and the Director can suspend an oak tree permit or building permit over it (17.51.040(E)). The city amended its oak rules in 2026, and the change was not yet in the online code when we read it, so ask Planning for the current text.
Laying out a gate near an oak
- Find the dripline on the side facing the drive and mark the zone and its halfway line on the ground.
- Put post footings in the outer half or beyond it. On a driveway gate, moving the gate a few feet along the drive can be enough.
- Route the opener's power trench around the inner half, or ask whether a solar opener would do away with the trench. More on the electric gates page.
- Keep the concrete, the steel and the truck out of the zone while the work is going on.
- If the drive also sits on a slope, read slopes and retaining walls before the post spots are final.
Does the ordinance cover Stevenson Ranch and Castaic?
No. This section is part of the City of Santa Clarita code. Stevenson Ranch and Castaic are unincorporated LA County, so the county's rules apply there instead.
Does it apply to an oak the owner planted?
On a single family lot, oaks the owner bought or planted on that property, other than as mitigation, are on the exemption list (17.51.040(B)(2)(j)).
Can a post go right under the canopy?
Only in the outer half of the zone without a permit, and on a small tree the whole zone may be 15 ft from the trunk. Under a large canopy, the outer half can still sit under the branches.