ABOR extends Regents’ Grant to develop technology that listens for bark beetles hiding inside Arizona’s trees

The Arizona Board of Regents today approved a no-cost extension of a Regents’ Research Grant, allowing university researchers to complete critical work that protects Arizona’s forests from one of their most destructive threats.

The NAU-led project is developing advanced acoustic technology to detect bark beetles inside living trees, so forest managers can find infestations before they spread. Bark beetles tunnel beneath the bark and cut off a tree’s water supply, and drought-stressed trees are especially vulnerable. Because infested trees must be removed quickly to contain outbreaks, early detection is essential to protecting forest health and limiting economic loss and forest destruction. 

“Every tree lost to bark beetles leaves Arizona’s forests weaker and more vulnerable to catastrophic wildfire,” said ABOR Executive Director Chad Sampson. “This extension keeps university researchers in the field, working to catch infestations early and protect our forests before that devastation spreads.”

Originally approved in FY2023, the project is building a handheld acoustic holography system that uses an array of precision microphones to capture the sounds beetles make inside a tree. Advanced software is designed to convert those sounds into a 3D map overlaid on a live camera image, pinpointing beetle activity without cutting into the tree. Led by Christopher Mann, professor of physics at NAU, the team is working with the Arizona Department of Forestry and Fire Management to test the system in the field.

“Protecting Arizona’s forests takes strong partnerships grounded in research and experience,” said Thomas Torres, director of the Arizona Department of Forestry and Fire Management. “Our public universities have been tremendous partners in translating research into real-world technology that our foresters can use in the field. We’re excited about its potential and eager to put it to work next summer.”

To date, the team has developed and refined a modular microphone-array prototype and a near-field acoustic holography processing pipeline. In the lab, the group has captured the chirps of live bark beetles, measured how sound travels through ponderosa pine bark and successfully reconstructed a test sound sent through it. Student researchers have also built a custom 16-channel microphone array with its own data acquisition system, which made its first recordings in late August 2026 and is now being calibrated. 

In addition, the team has published two papers. One, in the Journal of the Acoustical Society of America, details a new method that automatically discounts faulty or noisy microphone data, producing sharper, more reliable sound maps that pinpoint sound sources more precisely. The other, in the Journal of Sound and Vibration, describes a method that locates sound sources in three dimensions and can tell them apart by depth, a key step toward finding beetles beneath the bark.

Regents approved a 12-month, no-cost extension to allow the team to complete field validation of the acoustic detection and localization system. The extension also provides time to prepare the system and field protocols, carry out measurements in summer 2027 and complete analysis and refinement of the system. Beyond forest health, the same technology could help find leaks in Arizona's water pipes and track down noise from trains and industrial equipment.

"Bark beetles do their damage out of sight, and by the time a tree looks sick, they may already be moving on to its neighbors,” said Professor Mann. “That's why we're teaching our instruments to listen for them. Our lab results are very promising, and this extension gives us the time to take our system into the forest with state foresters and see what it can do on living trees."

Regents’ Research Grants are designed to accelerate solutions to Arizona’s most urgent needs by leveraging expertise across the state’s public universities – Arizona State University, NAU and the University of Arizona – in partnership with state agencies. Funded through the Technology and Research Initiative Fund, the program prioritizes near-term research opportunities that address the state’s most pressing challenges and deliver clear benefit to Arizonans.

You can learn more about the Regents’ Grants program and other projects funded by the board here.