Building around protected trees is a delicate matter – Austin takes protected trees seriously. If you’re considering building in Austin, you’ve probably heard about protected trees and the Austin tree ordinances.
If you’re building or flipping in Austin, you should also be familiar with the term CRZ, or critical root zone. This is an important factor that can affect how much you’ll be able to build on a given lot.
A tree survey is an absolute must in the first stages of developing or redeveloping a property in Austin. You’ll probably need an architect familiar with Austin city code to help translate that tree survey into building limitations. Understanding the limitations on a given lot are extremely important to understanding the value. Utilities and building footprints can get tricky fast when you’re building around protected trees.
Building around protected trees in Austin
All trees with 19” or greater diameter are protected. The measurement (they measure the circumference and divide by pi) is taken 4.5 feet from the ground. They don’t round up, so if your tree has an 18.9” diameter, then it’s likely not protected. You can remove an unprotected tree without a permit. Anything over 59.6904 inches around (circumference) is protected. The actual city ordinance is found here.
Can you remove a protected tree (19” to 23.9” diameter)?
Generally, yes. Either with a fee, with newly planted trees somewhere else on the property, or a combination of the two. You’ll need the city tree review application found here.
Can you remove a Heritage Tree (24” + diameter)?
A Heritage Tree is a tree with 24 inches or greater diameter. These are far less likely to be approved for removal. It requires a variance. The city arborist has to agree the tree is dead or fatally diseased – and you’re not likely to get approval for any other reason.
Texas Ash, Bald Cypress, American Elm, Cedar Elm, Texas Madrone, Bigtooth Maple, ALL Oaks, Pecan, Arizona Walnut, and Eastern Black Walnut.
It’s not just the trees themselves you have to worry about though, you also have the CRZ area surrounding the tree. To calculate the CRZ, take the tree diameter (inches) x2, convert to feet = CRZ diameter. So a 20″ tree has a 40 foot CRZ diameter (see visual aid below). A minimum of 50% of that CRZ is required to be left undisturbed to meet the regulation. More details about the CRZ and city code here.
Building around protected trees gets more stringent as you get closer to the tree. In the ¼ zone, which is ¼ of the diameter away from the tree in feet, you cannot dig at all. In the ½ zone, ½ of the diameter of the tree in feet, you may only dig 4”. So, a 20” diameter tree will have a 5’ perimeter in the ¼ zone, 5 more feet in the ½ zone, and 10 more feet in the CRZ. That’s a total of 20’ of CRZ from the base of the tree in either direction.
Here’s a helpful visual aid about CRZ from the City of Austin website.
If you’re building in the City of Austin, we’d love to be your direct lender. We fund new construction projects throughout Texas at competitive rates. Interested in investing in new construction projects instead of remodels? We can help!
More tree questions? Try the City of Austin FAQ regarding trees here.
You can also contact the City of Austin arborists here.