Turns out a small patch of city forest can do a lot. A new study found that sitting in a restored urban forest while listening to birdsong lowered people’s stress and improved their mood more than any other setting tested.

The study, published in Environmental Conservation, asked 106 students at North Carolina State University in the U.S. to sit outdoors in noise-canceling headphones at two spots on campus: a strip of riparian forest restored two decades ago, and a paved plaza facing a road intersection.

At each location, participants listened to 10 minutes of birdsong and 10 minutes of traffic noise, in random order. They then rated their stress, their positive and negative feelings, and how mentally restored they felt.

By changing both the place and the soundtrack, researchers could separate the effect of where someone sits from what they hear. Both helped on their own, and the biggest benefits came when they were combined.

Participants in the forest hearing birdsong reported an average stress score of 3.2 on an 11-point scale, compared with 6.4 for those on the plaza hearing traffic. The forest-and-birdsong pairing also produced the highest positive emotion and the strongest sense of restoration.

The two mixed conditions, forest with traffic and plaza with birdsong, fell in between. They performed better than the plaza-and-traffic combination, but not as well as the full forest-and-birdsong pairing.

“For participants who were in a green space listening to the birds, there were significant effects. Positive emotions went up, negative emotions went down, stress went down, and perceptions of feeling restored went up more than any other combination,” study lead author Nils Peterson, a professor in NC State’s College of Natural Resources, said in a press release.

The reverse held for people on the plaza hearing traffic.

For mental restoration, the physical setting mattered more than the soundtrack. The forest had a bigger effect than the birdsong. The authors said this may partly reflect the scale they used to measure restoration, which leans on how people perceive a place and may push them toward its visual features.

For stress and for positive and negative emotion, sound and setting carried roughly equal weight.

Cindy Frantz, an environmental psychologist who chairs the psychology department at Oberlin College in the U.S. state of Ohio and was not involved in the research, said the value of a study like this is that it reproduces laboratory findings in a real-world setting.

She warned against putting too much weight on a single result, which cannot show how long the effects last, if people grow used to them, or if everyone benefits equally.

Still, Frantz told Mongabay, the effects were notably large.

“The impact of natural environments and birdsong are not tiny ‘around the margins’ results,” she said. “Effect sizes this large suggest that the impacts they observed are likely to make a difference in people’s lived experiences.”

The forest used in the study was not old growth. It was a restoration completed in 2006, rebuilt from a degraded urban creek and now carrying more than 70 percent canopy cover on a working college campus.

That relatively young, human-made patch of forest produced the full effect, suggesting the benefits could be built into city parks with strategically placed seating and bird communities, rather than requiring access to remote wilderness.

“Designing outdoor spaces with birds in mind is not just a ‘tree-hugger’ priority, but also sensible public health policy,” Frantz said.

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