At 5 am on a recent trek, when the mist was still clinging to the high ranges stretching across the north of Sichuan province, Xiao Mei was already halfway up a mountain.

A backpack was pressed against her shoulders. Inside were memory cards for an infrared camera, notebooks and spare batteries. On other treks she also carries a sleeping bag and dry food when heading to one of the six remote field camps. Some of the camps have no electricity, no phone signal, and experience weather extremes.

"The longest I have stayed out was five days," she recalled. "You carry everything on your back."

The 36-year-old is head of the research and monitoring division at the Tangjiahe National Nature Reserve, which is located in Qingchuan county, Guangyuan city. Established in 1978 and designated a national nature reserve in 1986, Tangjiahe covers 40,000 hectares. Its focus is on conserving forest plants and wildlife. The primary conservation objectives are rare wildlife species, such as the giant panda, golden snub-nosed monkey and rare plant species, including the dove tree (Davidia involucrata), which is known as "a living fossil", and Fritillaria cirrhosa, or chuan bei mu in Chinese, a highly valued herb used in traditional Chinese medicine.

Xiao has spent 12 years in the park. However, when she first arrived, she almost left in the first three days.

She did not grow up dreaming of becoming a conservationist. She studied plant protection at an agricultural college in Chengdu, the provincial capital, where she was born and raised, and spent two years selling fertilizer in the city's rural outskirts.

"When I applied for Tangjiahe, it was just a job," she said frankly. "I didn't have a strong concept of what a nature reserve really meant. I liked plants. I saw that the dove tree, a nationally protected species, was here, so I applied."

The region was still recovering from the 2008 Wenchuan earthquake, ecotourism was underdeveloped, infrastructure was limited and life was quiet.

"I couldn't accept it at first. The work felt monotonous. You had to endure loneliness. On my third day, I wanted to leave," she said.

What changed her mind was not policy or promotion, but the forest itself.

"During patrols, you see things you can't see in the city — plants growing to their own rhythm, animals moving freely. There's a feeling that all living things have a spirit. That's when I began to calm down,"Xiao said.

She started reviewing infrared camera footage, sorting through patrol data, and noticing patterns. Curiosity replaced restlessness. "You begin to ask: What is missing in the data? What haven't we understood yet?" she said.

Tangjiahe is described as one of the ecological cores of the giant panda national park. Its subtropical mountain forests have largely escaped large-scale logging. The forest regenerates naturally, with minimal human disturbance. Population pressure inside the reserve is low, and wildlife encounter rates are unusually high.

"In some reserves, you need luck to see animals," Xiao said. "Here, if you enter at random, you can see many."

Tangjiahe's wild giant panda population is remarkably stable. Thirty-nine pandas were recorded in earlier surveys and by 2025, monitoring data confirmed a total of 41.

Since 2016, the reserve has built a DNA archive for the panda population, collecting genetic samples from more than 30 individuals annually. "Every year, we basically confirm over 30 individuals through DNA. It's very stable," Xiao said.