Tree Pruning

Austin Energy Forestry Division

It is our responsibility to deliver safe and reliable energy to our customers — to do so requires proper vegetation management. More than one out of three outages in our area are caused by vegetation and weather. During windy and stormy weather, swaying and broken tree limbs can rub against and hit or bring down power lines. Such impacts can cause service fluctuations, widespread outages, hazardous conditions, and fires.

Trees that grow too closely to power lines also pose an unnecessary risk to customers who depend on uninterrupted power for life support.

Unpruned trees:

• increase the likelihood of fires from arcing electricity.
• can cause serious injuries or fatalities to anyone who climbs trees too close to power lines.
• can cause electrical shock and injury to anyone in the vicinity of an energized tree.

For these reasons, the National Electrical Safety Code requires Austin Energy to keep branches clear of power lines.

According to the Texas Wildfire Mitigation Project, power lines caused more than 4,000 wildfires in Texas from 2009 to 2013. The Austin Fire Department's Wildfire Division says 60% of structures in Austin are located in wildfire-prone areas.

Watch what happens when wind causes tree vegetation to touch energized power lines:

Storm Response and Debris Removal

During widespread storm events, power restoration is our priority. Branches can break off or sag and damage power lines, especially during storms with heavy winds, hail, sleet, and ice. Often, our crews must prune damaged tree limbs before safely repairing the electric system.

Brush resulting from power restoration will not be removed by Austin Energy or our contractors. Check the Austin Resource Recovery residential guidelines and schedule for curbside brush collection.

Pruning Practices

In 2019, Austin Energy will increase its tree pruning clearances to the levels listed below to increase reliability and safety and to keep our customers and communities safe. These new clearances will help us adapt to and address the increasing threat of wildfire and extreme weather.

These tree pruning clearances mean that your trees will be pruned enough to keep limbs clear of the power lines for 4 to 5 years. However, some fast-growing species may require pruning during the mid-point of cycles to maintain proper clearances from energized lines. These pruning cycles are ideal to protect the health of your trees, ensure public safety and reliability, and assist with reducing the significant expense of tree pruning.

Austin Energy's pruning cycle requires work planning along more than 2,400 miles of power lines. Each year, hundreds of miles of Austin Energy power lines are scheduled for tree pruning or tree removal on 9,000 to 12,000 properties a year.

Establishing Clearances:

• Fast-growing species (e.g., Ligustrum, China Berry, Hackberry, and Pecan): 11-15 ft.
• Slow-growing species (e.g., Cedar, Cedar Elm, and Juniper): 7-10 ft.
• Along high-voltage transmission cables: minimum clearance is 25 ft.
• To ensure pruning cuts follow best practices additional clearances may be required.

Factors We Consider:

• Austin Energy uses various factors, such as tree species and time-of-the-year, to determine the best approach to prune the trees on your property. 
• Environmental: We consider oak wilt and bird habitats. We make every effort to avoid pruning red oak and live oak trees between February and June when oak wilt is more likely to spread. To protect bird habitat areas, when possible, we avoid pruning from March to September (applies to undeveloped areas west of MoPac).
• Circuit, line fuses, and customer ticket requests: We prune trees along a circuit from beginning to end on maintenance schedules. We prune trees along a line fuse section or area identified in a ticket request. If a portion of the circuit or line fuse is not pruned and a tree limb falls on the line, the entire area may experience a power outage.

Benefits of Proper Vegetation Management

• Maintains public safety near energized power lines and promotes a more reliable system.
• Supports the City of Austin's and the Austin Fire Department's Firewise Program and enhances public safety awareness to minimize tree/wire conflicts to reduce fire risk.
• Provides utility crews safe access to equipment for repairs, which allows for quicker power restoration.
• Protects and promotes the health of your trees.

For More Information

Please visit our Tree Pruning FAQs to find answers to commonly raised questions about our tree pruning program. If you need more information, please call Customer Care at 512-494-9400 or email the Austin Energy Forestry Division.