CHANGSHA -- A camphor tree in Xinyuan village of Hengshan county, Central China's Hunan province, stood strong for three centuries before it began to falter in recent years.

When Wu Lei, a specialist in ancient tree conservation, arrived in the village, he had a surgical plan and hoped that the giant tree could be returned to its prime.

After cordoning off the area around the tree, Wu and another worker ascended into its canopy on a crane. There, they trimmed dead and dying branches with a chainsaw and carefully sealed exposed cuts with a wound-healing paste.

Beneath them, other workers drilled through the surrounding concrete and injected nutrients 3 meters deep into the ground every half hour to reach the tree's struggling roots.

A handful of village locals gathered quietly in a nearby courtyard to watch the tree surgery unfold.

The tree's decline began in 2021, when the construction of a nearby flood-control embankment compacted much of its root system, straining its ability to absorb water and nutrients.

"We see classic symptoms of crown dieback like yellow leaves, early leaf loss and bare skeletal branches," said Wu, deputy director of the ancient tree conservation and research center at the Central South University of Forestry and Technology.

Without treatment, the camphor tree would likely have died within two to three years, said Deng Shicheng, head of the landscaping team assisting with the restoration efforts.

"To heal an ancient tree, you have to begin with how it 'feels,'" Wu said. "Just like people, trees can suffer from overtreatment or mistreatment."

The restoration was initiated by the county's forestry bureau in March and underwent a full review before approval.

Ancient trees can decline due to both human activity and natural causes, such as lightning strikes or insect infestations. Each year, forestry departments across Hunan assess the health of registered ancient trees. Simpler treatment plans are handled locally, while complex or severe cases are referred to provincial experts like Wu.

Hunan is home to around 240,000 registered ancient or notable trees. As of last year, the province had rescued nearly 4,000 endangered trees and revitalized another 30,000 in decline.

This year, officials aim to digitize the records of each tree and organize 200 public education events to raise awareness and encourage broader participation, according to Ou Riming, an official of the provincial forestry department.

Hunan's efforts are part of a national campaign to protect ancient and notable trees. The former are defined as those that are over 100 years old, and the latter as those with historical, cultural or ecological importance.

In Beijing, experts conduct regular checkups of the ancient trees lining the city's UNESCO-listed Central Axis. In Chengdu, southwest China, a team of tree doctors formed in 2014 has assessed thousands of ancient trees citywide.

In January, China introduced its first national-level regulations to protect ancient and notable trees, aligning with the country's broader goals of building an ecological civilization and preserving cultural identity.

A national survey conducted from 2015 to 2021 identified 5.08 million ancient or notable trees across China.

The full rehabilitation of the camphor tree in Hunan is expected to take about a year and cost 30,000 yuan (about $4,163).

The team will continue providing follow-up care, including fertilization and pruning, while training locals in long-term maintenance.