LHASA -- In the early morning in Nanshan Park, or southern mountain park, located in Lhasa, capital of Southwest China's Xizang autonomous region, forest ranger Tashi Chophel arrived at a monitoring station and started watching over the forest he has protected for 13 years via dozens of surveillance screens.

The 44-year-old man oversees tree planting, irrigation, pest control and other tasks needed to ensure healthy forest growth.

"The trees are like my children. Watching them grow daily fills my heart with joy," said Tashi Chophel, adding that some of the first trees planted in the area had naturally propagated second and third generations.

The park hosts more than 120 tree species -- and Tashi Chophel can name each one.

Lhasa is nestled in a narrow river valley, where the Lhasa River winds through the city, flanked by mountains to the north and south.

Directly south of the Potala Palace, the green-clad southern mountains face the urban area across the river, with shrubs and trees interspersed across the mountain slopes, creating a lush landscape.

"Over a decade ago, these mountains were bare, with winds sweeping up sand and dust. Even birds avoided the area," Tashi Chophel recalled. "Now, when you whistle in the forest, birds call back as if conversing with you."

To curb grassland degradation and desertification, and to improve living conditions for residents, Lhasa launched an afforestation project in the southern mountains in 2012. Over the following five years, tree planting efforts transformed once-barren hills into what is now Nanshan Park.

Thanks to continued greening efforts, the park is currently home to more than 800,000 trees -- covering an afforested area of over 4,350 mu (about 290 hectares).

In 2021, Lhasa kicked off a new greening project for its northern and southern mountains. As part of this initiative, Nanshan Park became a landmark project, as it is Xizang's first large-scale ecological construction and restoration effort in a river valley.

In the early stages, the rugged terrain meant saplings had to be hauled by mule from the base of the mountains at 3,700 meters above sea level to planting spots reaching over 4,100 meters. It was a demanding and time-consuming task, with limited daily deliveries and poor sapling survival rates.

"At that time, we had to rely on manually watering the saplings using hoses, but in winter the pipes often froze and became clogged, making it hard for the young trees to survive," recalled Tashi Chophel.

Today, technology has breathed new life into the ecological development of Nanshan Park. Drone transport has become one of the methods available for delivering saplings.

Last year, Tashi Chophel earned a professional agricultural drone operation certificate and he can now skillfully pilot large drones to deliver saplings directly to steep planting sites. Each trip can carry 35 to 40 kg of saplings -- significantly improving efficiency.

Modern irrigation systems have also made tree maintenance more efficient. "Now, we have automated watering at the mountain sites, and we also drive water trucks up the slopes. In a single day, we can water more than 1,000 trees, and they're growing better than ever," Tashi Chophel said with a smile.

Data shows that in 2024, the new greening project had added 177,200 mu of newly afforested area -- with a seedling survival rate of over 92 percent across 38 planting zones.

Standing at a viewing platform, local visitor Lodro Nyima looked out over the landscape and described the scene before him as nothing like the barren southern mountain view he had encountered in the past. "With so many trees, Lhasa now feels more alive," he said.