Can a protected oak tree stop an ADU in Granada Hills?

Which trees on my lot does Los Angeles protect?

Six native species are protected on private property in the City of Los Angeles under the Protected Tree and Shrub Ordinance, as amended by Ordinance No. 186,873 in 2021. Four are trees and two are shrubs ²¹:

• Oaks: valley oak, coast live oak (the city calls it California live oak) and any other oak native to California, except scrub oak ².
• Southern California black walnut
• Western sycamore
• California bay
• Mexican elderberry (shrub)
• Toyon (shrub)

Size is the second test. A plant of one of these species is protected once its trunk measures at least 4 cumulative inches in diameter at 4.5 feet above the ground ¹. Cumulative means a tree with several trunks is measured by adding them together, so a multi-trunk oak that looks small can still qualify.

In Granada Hills this is not a rare situation. The city's own guide says coast live oak grows throughout the city, including the San Fernando Valley ⁷, and black walnut is common on north-facing slopes in hilly neighborhoods ⁸, which describes the lots along the foothills north of the 118.

Do I need a permit if I am not cutting the tree down?

Yes, often you do. A permit is required not only to remove or relocate a protected tree, but also for potentially destructive activities that may result in its death ³.

The code defines removal broadly. Any act that will cause the tree to die counts, including damage to the root system from equipment or machinery, or changing the grade by digging or filling in the drip line area around the trunk ⁴. The drip line is roughly the edge of the canopy. For an ADU, that means footing trenches, a slab excavation, a new sewer or water line, or even parking a loaded truck under the canopy can put you inside the rule while the tree is still standing.

This is the part most homeowners miss. The question is not whether you plan to keep the oak. It is whether your foundation, trenches and staging area reach under it.

How can I tell if my tree is protected?

Start with the city's free Photographic Guide to Protected Trees and Shrubs. It shows the leaves, bark, acorns and fruit of each protected species. The guide itself says it is a starting place, not a formal identification tool, and does not replace a report from a City-defined Tree Expert ⁶.

A simple first pass:

1. Look at the whole tree, not one leaf. Coast live oak keeps dark green, cupped, spiny-edged leaves all year; valley oak drops its deeply lobed leaves in winter.
2. Measure the trunk circumference at 4.5 feet off the ground and divide by 3.14. For several trunks, add the diameters together. At 4 inches or more, treat it as protected ¹.
3. Check the neighbor's side of the fence. LADBS asks applicants to identify protected trees on or adjacent to the lot and show them on the plans ⁹, because roots and canopy do not stop at the property line.

If any answer is uncertain, a Tree Expert settles it. Under the ordinance that means an ISA Certified Arborist who is also a licensed pest control advisor or landscape architect, or a Registered Consulting Arborist ⁵.

Where does the tree come up in ADU plan check?

It comes up at plan check, and it can add time. LADBS refers protected trees shown on the plans to StreetsLA's Urban Forestry Division (UFD) as a clearance, and its bulletin warns that a UFD clearance may delay the building permit and recommends contacting UFD right away ¹¹.

The order that works:

1. Design: show every protected tree on or next to the lot on the site plan ⁹. LADBS asks applicants to design structures that limit or eliminate impact on existing trees ¹⁰.
2. Plan check: request the UFD clearance through the city's online Customer Service Request system, which StreetsLA set up for clearances on City Planning and LADBS permits ¹⁴. An arborist report may be required.
3. Construction: the approved tree report sets conditions, including protective fencing around the Tree Protection Zone, kept up for the whole job ¹².

Putting the tree on the plans from day one costs less than a correction notice after the drawings are done.

Can the city deny my ADU because of an oak tree?

Not simply for being an ADU, but the tree rules still apply to the work. State law requires cities to approve qualifying ADUs ministerially, and HCD says the four categories of ADU in Government Code section 66323, such as an 800-square-foot detached unit, are only subject to the standards in that section ²⁰.

Nothing we found in state ADU law or in HCD's handbook addresses tree ordinances directly. In practice, LADBS still routes protected trees to Urban Forestry during plan check ¹¹, and StreetsLA says it will deny a removal permit if the tree can be preserved by redesign ¹⁵. So the realistic risk is not a flat no on the ADU. It is a no on removing the tree, which sends you back to move or reshape the unit.

As of October 2026, plan as if the tree rules apply. If you believe a specific condition conflicts with state ADU law, that is a question for a land use attorney, not for a guess at the counter.

What if the tree has to come out?

Then you apply to Urban Forestry for a removal permit, and the city sets the replacement. The application needs a Tree Expert's report ⁵. UFD inspects the site, and if three or more trees are to be removed, a report goes to the Board of Public Works ¹⁶.

The ordinance lets the city require at least four replacements of a protected variety for each protected tree removed ¹⁷, each at least a 15-gallon specimen and 7 feet tall ¹⁸. The permit names the species, number and size of the replacements ¹⁹. On a typical Granada Hills lot, four new oaks also need room, which is one more reason to keep the original.

Do not remove the tree first and ask later. If a protected tree is removed without a permit, the city can withhold or revoke building permits on the property for up to 10 years ¹³. That would stop the ADU far more completely than the oak ever could.

How do I place the ADU so it stays clear of the roots?

Decide where the tree's protection zone is before anyone draws a floor plan. A Tree Expert can mark the zone; the code's line of concern is the drip line around the trunk ⁴, and LADBS uses the term Tree Protection Zone in construction conditions ¹².

Practical moves that usually help:

• Site the unit outside the canopy and keep the long side of the building facing away from the trunk.
• Route utility trenches around the zone. A new sewer lateral or electrical line dug across the roots is the same root damage as a footing.
• Consider a garage conversion if the existing garage sits near the tree. Working inside an existing structure may involve less new digging than a new foundation, though a Tree Expert should still confirm it.
• Keep staging and material piles out from under the canopy.

Granada Hills lots give you room to work with. Across 13,337 single-family parcels in ZIP 91344, the median lot is 8,345 square feet ²³, and owners pulled 210 ADU permits there in 2025 ²². If your lot also sits near the foothills, remember that brush clearance must follow the same tree rules ²¹.

Where the tree is, how wide the canopy spreads and whether the neighbor's oak hangs over the fence is the kind of thing a lot check settles before you pay for plans.

Quick answers

Sources

1. Photographic Guide to the City of Los Angeles Protected Trees and Shrubs (Sept. 2024), StreetsLA, Urban Forestry Division. Facts checked 2026-10-08
2. Ordinance No. 186,873 (protected tree and shrub amendments), as published, LAMC Sec. 46.01, Los Angeles City Clerk. Facts checked 2026-10-08
3. Photographic Guide to the City of Los Angeles Protected Trees and Shrubs (Sept. 2024), permit requirement, StreetsLA, Urban Forestry Division. Facts checked 2026-10-08
4. Ordinance No. 186,873 (protected tree and shrub amendments), as published, LAMC Sec. 46.00, Los Angeles City Clerk. Facts checked 2026-10-08
5. Photographic Guide to the City of Los Angeles Protected Trees and Shrubs (Sept. 2024), Tree Expert report, StreetsLA, Urban Forestry Division. Facts checked 2026-10-08
6. Photographic Guide to the City of Los Angeles Protected Trees and Shrubs (Sept. 2024), purpose of the guide, StreetsLA, Urban Forestry Division. Facts checked 2026-10-08
7. Photographic Guide to the City of Los Angeles Protected Trees and Shrubs (Sept. 2024), California live oak, StreetsLA, Urban Forestry Division. Facts checked 2026-10-08
8. Photographic Guide to the City of Los Angeles Protected Trees and Shrubs (Sept. 2024), Southern California black walnut, StreetsLA, Urban Forestry Division. Facts checked 2026-10-08
9. Information Bulletin P/ZC 2024-022: Guidelines and Requirements for Regulated Trees, design phase, LADBS. Facts checked 2026-10-08
10. Information Bulletin P/ZC 2024-022: Guidelines and Requirements for Regulated Trees, design guidance, LADBS. Facts checked 2026-10-08
11. Information Bulletin P/ZC 2024-022: Guidelines and Requirements for Regulated Trees, plan check phase, LADBS. Facts checked 2026-10-08
12. Information Bulletin P/ZC 2024-022: Guidelines and Requirements for Regulated Trees, construction phase, LADBS. Facts checked 2026-10-08
13. Information Bulletin P/ZC 2024-022: Guidelines and Requirements for Regulated Trees, warning and consequences, LADBS. Facts checked 2026-10-08
14. Request Urban Forestry Clearances, StreetsLA. Facts checked 2026-10-08
15. Private Property Native/Protected Tree Removal Permits, StreetsLA. Facts checked 2026-10-08
16. Private Property Native/Protected Tree Removal Permits, approval step, StreetsLA. Facts checked 2026-10-08
17. Ordinance No. 186,873 (protected tree and shrub amendments), as published, replacement (LAMC Sec. 17.05 R), Los Angeles City Clerk. Facts checked 2026-10-08
18. Ordinance No. 186,873 (protected tree and shrub amendments), as published, replacement size (LAMC Sec. 17.05 R), Los Angeles City Clerk. Facts checked 2026-10-08
19. Ordinance No. 186,873 (protected tree and shrub amendments), as published, permit conditions (LAMC Sec. 46.03), Los Angeles City Clerk. Facts checked 2026-10-08
20. Accessory Dwelling Unit Handbook (updated January 2025), California Department of Housing and Community Development (HCD). Facts checked 2026-10-08
21. Protected Trees and Shrubs Ordinance, Los Angeles Fire Department. Facts checked 2026-10-08
22. Building Permits Issued from 2020 to Present (dataset pi9x-tg5x), LADBS via City of Los Angeles Open Data. Facts checked 2026-10-08
23. LA County parcel layer (LACounty_Parcel), Los Angeles County Assessor GIS. Facts checked 2026-10-08

Greenlight is not a contractor, architect or engineer, and this is not legal advice. Rules change; every fact here shows the date we last checked it.