Tree Canopy Expansion: Columbus Drive
Location: A 6,000-square-foot area near the Violet Crown Trail trailhead at Columbus Drive, Zilker Park
Status: Complete; trees will be monitored through year three
Overview
This project restored native tree canopy on a site identified with the potential to improve habitat connectivity, increase water infiltration, and reduce urban heat. The site had been overtaken by invasive ligustrum. It is now planted with 140 native trees arranged in tree mottes, clusters that mimic how trees naturally group and support each other.
The project supports three goals central to Zilker 351's Ecological Health work: protecting water quality and habitat downstream in Barton Creek and Barton Springs, building climate resilience through shade and cooler trail temperatures, and engaging the community directly in caring for the park.
What We Did
- Removed invasive ligustrum from the 6,000-square-foot site
- Chipped the removed material on-site to create mulch for the new trees
- Built soil berms and swales to slow and filter stormwater runoff from nearby roads
- Installed a gravity-fed irrigation system supplied by a cistern refillable by rainwater or water truck, independent of city water infrastructure
- Planted 50 native canopy trees and 90 native understory trees in a tree motte formation
- Hosted a volunteer planting and mulching day in partnership with Austin Parks Foundation
- Installed protective fencing around the new plantings
- Began three years of monitoring for water and mulch needs
Results
- 90% tree survival rate, exceeding the project's 80% target
- 140 native trees established across the restored site
- 60 volunteers participated in the planting day, more than the 50 originally anticipated, with several groups requesting to join on their own
- Erosion from Columbus Drive runoff has visibly decreased, aided by the berms, mulch, and water uptake from the young trees
- Substantial invasive ligustrum removed and replaced with native woodland