Environmental commissioners brush up on tree preservation 101

On Wednesday, the Environmental Commission revisited heritage tree ordinances, general preservation efforts going on around Austin and the rules for protecting and building around trees, with city arborist Naomi Rotramel and Community Tree Preservation Division Manager Keith Mars.

Austin’s original tree ordinances were first adopted in 1983, largely thanks to the early advocacy of Margret Hofmann, who served on City Council in the ’70s. The Heritage Tree Ordinance was passed in 2010.

Under the 1983 ordinances, trees larger than 19 inches in diameter receive limited protections, including the necessity for tree permits for removal or activities that impact the trees. All species, including invasive trees, are protected under the ordinances.

“Nineteen inches in diameter is the same as 60 inches in circumference,” Rotramel explained. “So if you can wrap a seamstress tape around a tree, it’ll be protected.”

Certain species of trees over 24 inches in diameter, such as oaks, pecans, elms and walnuts are considered heritage trees. Heritage trees require variances for removal, though the variances can be implemented administratively if the trees are under 30 inches in diameter. Otherwise, the variances can only be administered following a public process.

“The closer you get to the tree, the more critical it is to keep those roots alive,” Rotramel said.

The roots of a 24-inch tree span 20 feet outward, so any construction must fall outside the inner half of the tree’s critical root zone.

“Thanks to the ordinance, we’ve preserved over 70,000 inches of heritage trees reviewed, at a 95 percent preservation rate,” Rotramel said, noting that Austin’s preservation rate amounts to a national model.

“Our tree regulations are an embodiment of our home rule authority,” Mars said, referring to the rights of local governments to pass rules and ordinances, so long as they don’t conflict with the broader state law.

“The tree must be preserved, unless it prevents a reasonable use or reasonable access to the property,” Mars said, explaining that how “reasonable use” is defined is determined by the city.

Trees are not only critical to climate outcomes, they reduce energy costs by $20 million a year.

“Trees benefit all of us,” Mars concluded.

Destroying protected trees is a class C misdemeanor bringing fines of up to $2,000.

Photo by Elizabeth Genovise, CC BY-SA 3.0.

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