Austin tree rules: protected trees, heritage trees and removal permits
| Diameter | Species | What follows | |
|---|---|---|---|
| Protected tree | 19 in + | Any | Removal requires a permit |
| Heritage tree | 24 in + | Listed species only | Narrower removal criteria |
| Site plan / demolition exemption | more than 8 in | Any | Disturbing one can void the exemption |
Three different diameter thresholds, all measured four and a half feet above natural grade. They answer different questions and are routinely conflated.
Protected and heritage are not the same thing
Both terms get used loosely, and the difference decides how hard a tree is to remove.
Protected tree — 19 inches or more, any species. Measured at diameter, four and a half feet above natural grade. That is the trigger for needing a permit at all.
Heritage tree — 24 inches or more, and one of eleven listed species. Both conditions. A 30-inch tree of an unlisted species is protected but not heritage.
The eleven species:
- Texas Ash
- Bald Cypress
- American Elm
- Cedar Elm
- Texas Madrone
- Bigtooth Maple
- All Oaks
- Pecan
- Arizona Walnut
- Eastern Black Walnut
"All Oaks" is doing most of the work in Central Austin. A mature live oak of 24 inches is common on an older lot, and it is a heritage tree.
One structural detail worth knowing: the code says the species list may be supplemented, but not reduced, by rule. It is a ratchet — the list can grow administratively and cannot shrink.
HERITAGE TREE means a tree that has a diameter of 24 inches or more, measured four and one-half feet above natural grade, and is one of the following species: Ash, Texas; Cypress, Bald; Elm, American; Elm, Cedar; Madrone, Texas; Maple, Bigtooth; All Oaks; Pecan; Walnut, Arizona; Walnut, Eastern Black. This list of eligible heritage tree species may be supplemented, but not reduced, as prescribed by rule.
The eight-inch number is a different test
This is where people get caught, because eight inches is nowhere near either protection threshold — and yet it can stop a project.
The site plan exemptions use eight inches as their trigger. Demolition of a structure is exempt from site plan review only if trees larger than eight inches in diameter are not disturbed and the site is not cleared. Clearing for surveying is exempt unless a tree more than eight inches is to be removed.
So an eight-inch tree does not need a removal permit — it is nowhere near protected — but disturbing it can pull an otherwise-exempt demolition into full site plan review. Two entirely separate consequences from two entirely separate numbers.
When you need a permit, and when you do not
§25-8-621(A) is the rule: a person may not remove a protected tree unless the Planning and Development Review Department has issued a permit.
Two exceptions:
- Storm damage. A damaged protected tree that is an imminent hazard to life or property may be removed without a permit if it is removed within seven days of being damaged. The department may extend that deadline for widespread and extensive storm damage.
- Already approved. A protected tree identified for removal on an approved preliminary plan, final plat or site plan may be removed without a separate permit.
The seven-day window is short and runs from the damage, not from discovery. If a tree comes down in a storm and is genuinely hazardous, the clock is already running.
The removal criteria are narrow
§25-8-624 sets out when removal may be approved, and the grounds are limited. The tree must, broadly, be one that:
- prevents reasonable access to the property;
- prevents a reasonable use of the property;
- is an imminent hazard to life or property, where the hazard cannot reasonably be mitigated without removing the tree;
- is dead; or
- is diseased, subject to further conditions.
Read the second and third carefully. "Prevents a reasonable use" is not "is inconvenient", and "the hazard cannot reasonably be mitigated without removing the tree" puts pruning, cabling and bracing ahead of removal. These are not tests a project passes by preferring a different layout.
The critical root zone is the number that actually constrains the plan
Permits and heritage status get the attention, but the thing that moves a house on a site is the critical root zone, and its definition is unusually easy to apply:
The CRZ is a circle centered on the trunk whose radius in feet equals the trunk diameter in inches. A 24-inch tree has a 24-foot radius CRZ. Nested inside it are the Half CRZ (half the radius) and the Quarter CRZ (a quarter of the radius).
The Standard Preservation Criteria then work outward from the trunk:
- Quarter CRZ — no cut or fill at all.
- Half CRZ — must be protected in its entirety, except cut or fill of four inches or less.
- Full CRZ — at least 50% of its total area preserved at natural grade, with natural ground cover.
And the City Arborist may enlarge it. For species less resilient to development — post oak is named — and for high value trees, rare trees or sensitive site conditions, the request can be for a CRZ 1¼ to 1½ times the minimum.
Trees decide layouts more often than clients expect
On an older Central Austin lot the mature oak is usually the single least negotiable thing on the site. It is a heritage tree at 24 inches, the removal criteria will not be met simply because it sits where the house would be convenient, and its root zone constrains foundation, drainage and access.
We survey trees before drawing anything, and the good outcome is usually a plan that works around the tree rather than an argument about removing it. On a split it can be decisive — an oak in the middle of the parent lot can determine where, or whether, a new lot line can go.
The demolition trap is the one worth repeating. Clients assume clearing the lot is straightforward, and an eight-inch tree in the way of the equipment turns an exempt demolition into a reviewed one.
Common questions
Send us an address and we will tell you what we find
We do this research ourselves on every project we take on — zoning, floodplain, watershed, trees, whether it is a legal lot. Send us an address and we will run it and tell you what we find. It works the same whether you own a vacant lot, a house you are thinking of adding a unit to, or a house you are thinking of replacing. No charge and no strings, and if it is a bad lot we will say so.
Send us an addressWe are homebuilders, not the City of Austin. This page explains how we read the code in practice — it is not legal advice and it is not an official determination. Always confirm with Austin Development Services before you rely on it for a project. The authoritative text is the Austin Land Development Code; permitting questions go to Austin Development Services Department.