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Can Drones Help Maintain a City’s Trees?

December 28, 2021

Leveraging Drone Flight Services for Your City

In many cities, the department that oversees tree maintenance is faced with constant challenges and limited resources for meeting them. In fact, outside of special interest groups, non-profits, and academic groups, very few communities have strategic arborist capabilities.

This is the case in Winchester, Virginia, where the city’s Tree Division is limited in its ability to conduct strategic and comprehensive tree surveys. Despite limitations in resources, the city has proudly been a Tree City USA community for over thirty years, and works to maintain the health and safety of all trees on city streets and in public right-of-way areas.

As in most cities, arborist work in Winchester is largely reactionary, with city personnel responding to tree-related incidents after they’ve already happened, instead of preventing them through proactive surveys and maintenance. 

In cities, arborist work is crucial for:

  • Preventing hazards to people or damage to homes and buildings caused by falling trees. 
  • Preventing dangers caused on the road by overgrown trees obstructing drivers’ line of sight.
  • Preventing hazards to power lines and other critical infrastructure.
  • Ensuring the continued health of the city’s trees and preventing invasive species from killing them off.

Yet even if city personnel in Winchester had the additional resources to conduct proactive arborist work, doing it manually would not be ideal since it is slow and time-consuming work.

What If Tree Surveys Could Be Conducted by Drone?

When Winchester partnered with DroneUp as the first city in its Innovative Municipalities Initiative, leadership in the city wanted to see whether there was an application through which drones could contribute to the community’s tree maintenance and care. 

DroneUp assessed the Tree Division’s challenges as well as strategic initiatives to improve efficiencies and effectiveness in carrying out their duties to the public. When presented with three drone operations that could fulfill this potential in one fashion or another, the arborists were most interested in the potential value in using drones to conduct tree surveys in the city. (The tree survey DroneUp conducted and their resulting assesments are covered in the next section.) 

Drones are already commonly used for an array of inspection methods that test materials or objects without damaging them. For tree surveys, drones are commonly used by the U.S. Forest Service and the U.S. Department of the Interior, as well as by many land trusts and private companies for which tree health is of interest. Drones can collect visual data reflecting the position of trees relative to city infrastructure or buildings, and they can also collect multispectral data for health mapping and early disease detection in trees. 

In Winchester, the Lanternfly has ravaged the trees in parts of the city. Personnel in the city’s Tree Division wanted to see whether drones could help them understand the encroachment the flies had made into the city’s trees so they could make a plan to fight back and save them.

The city’s reactive process for dealing with tree-related incidents was also expensive. Clearing and restoring a power line taken down by a falling tree, for instance, is much more expensive than pruning or removing the tree in advance and preventing the downed line altogether. If drones could quickly and inexpensively survey the city’s trees, it would help the city to be more reactive in their maintenance.

This initiative became the fifth and final test undertaken as part of DroneUp’s Innovative Municipalities Project in Winchester. 

Results from the Drone Tree Survey Test

The aerial arborist test took place on a Friday in September, in a predetermined sample area that spans 106 acres within the city of Winchester.

On arrival, it was clear to the DroneUp team why the Winchester arborist had chosen this location for the test. The area was full of overgrown trees, many of which were enmeshed with the power lines running down the residential streets.

Flying at 200 feet in the air with a DJI Inspire 2 equipped with an RGB visual sensor, the DroneUp team collected visual data across the entire area. Data was collected both in a residential area and in a neighboring park called Jim Barnett Park, which had been mapped the day before as part of a surveying test.

After collecting visual data by drone, it was then processed into a high-fidelity 3D map that allowed clear visibility of the condition of the trees and their locations relative to power lines, roads, and other critical infrastructure.

So—what were the results of the test?

The test was a success! DroneUp team members were able to collect all the data needed to map the trees in the 106-acre area within about two hours. A manual approach would have taken about 1.5 days of work, or 12 hours, which means that the drone reduced the time needed for the survey by almost 85%.

The high-resolution visual data that DroneUp collected during the test gave Winchester’s Tree Division never-before-seen visibility of the residential trees that they could use to conduct health, risk, and upkeep analysis. 

Data collected in the drone operation allowed Winchester’s arborists to actually perform multiple assessments on the captured area:

  • Survey power line clearance.
  • Determine tree encroachment of sidewalks and city streets.
  • Identify extreme hazards and health concerns, including uprooted trees, broken branches, and dead trees.

What’s Next?

The test proved that using drones to survey trees in the city of Winchester has the potential to significantly improve how the city’s Tree Division does its work.

Using these drone surveys to uncover tree-related issues before an incident occurs will reduce hazards to people, buildings, and infrastructure, as well as reducing the costs associated with repairs related to falling trees.

Now that the ability of drones to perform tree surveys has been demonstrated, here’s what DroneUp and Winchester are planning next:

  • Develop a standard operating procedure (SOP) for scaled drone-based tree surveys.
  • Test the use of multispectral imaging collected by drone to see how it can further support tree maintenance efforts.
  • Explore the creation and use of new takeoff / landing areas for drone operations in the city, both for tree survey work and other types of drone work.

About DroneUp’s Innovative Municipalities Project 

The Innovative Municipalities Project is an initiative created by DroneUp to offer drone flight services to cities to help them become more efficient while realizing significant savings.

The project’s core focus is to test how drones can help cities improve their work from one day to the next by leveraging drone technology.

Through close collaborations between DroneUp and city governments, project leaders identify and test custom-built solutions for each city’s unique need to employ advanced drones and software to help cities save money, improve efficiency, and, in some instances, keep people out of harm’s way.

Learn more about DroneUp’s Innovative Municipalities Project.