Herdswoman Qime Garde shows a newly-harvested caterpillar fungus in Biru County of Nagqu, southwest China's Tibet Autonomous Region, May 25, 2022. (Xinhua/Liu Ying)

NAGQU, May 31 (Xinhua) -- On the prairie of over 4,700 meters above sea level in Biru County of Nagqu, southwest China's Tibet Autonomous Region, herdsmen are busy hunting down caterpillar fungus at the harvest time.

Biru County is a key site of yielding caterpillar fungus, an expensive ingredient in traditional Chinese medicine. Found only at high altitudes, the fungus, known in China as "winter-worm summer-grass," is said to be effective in boosting the immune system.

The caterpillar fungus harvest time lasts 45 days. For local herdsmen, collecting this precious fungus offers them seasonal jobs and increases their income.

Trekking on the alpine ground, searching for the tiny caterpillar fungus as small as an apple stalk, fungus diggers must brave harsh weather conditions from sunrise till sunset.

Fungus diggers use an ice pick to prod the earth and dig a hole about 10 centimeters deep. After plucking the fungus from the soil, the diggers fill up the hole with the removed earth to restore the natural soil structure for fostering caterpillar fungus in the coming year.

As the sun sets, the herdsmen return to their tents with the harvested caterpillar fungi after spending a day working on the highlands. They always make a point of taking away the trash with them produced during the long working day.

During the caterpillar fungus harvest season, the herdsmen make their home temporarily in tents in the valley. Here, rows of solar panels illuminate the night sky as their tents are all facilitated with solar energy. And inside their tents, the herdsmen enjoy their leisure time after a harsh working day, listening to the raindrops on their rooftop.

People rally before departing for caterpillar fungus collection in Lainqu Township, Biru County of Nagqu, southwest China's Tibet Autonomous Region, May 26, 2022. (Xinhua/Jiang Fan)

People depart for caterpillar fungus collection in Lainqu Township, Biru County of Nagqu, southwest China's Tibet Autonomous Region, May 26, 2022. (Xinhua/Jigme Dorje)

Herdsmen hunt down caterpillar fungus in Biru County of Nagqu, southwest China's Tibet Autonomous Region, May 25, 2022. (Xinhua/Jigme Dorje)

A caterpillar fungus sprouts on the grassland in Biru County of Nagqu, southwest China's Tibet Autonomous Region, May 25, 2022. (Xinhua/Jigme Dorje)

People depart for caterpillar fungus collection in Lainqu Township, Biru County of Nagqu, southwest China's Tibet Autonomous Region, May 26, 2022. (Xinhua/Jigme Dorje)

The morning view is pictured at a caterpillar fungus collecting site in Lainqu Township, Biru County of Nagqu, southwest China's Tibet Autonomous Region, May 26, 2022. (Xinhua/Jigme Dorje)

A herdsman cleans a newly-harvested caterpillar fungus at a caterpillar fungus collecting site in Lainqu Township, Biru County of Nagqu, southwest China's Tibet Autonomous Region, May 25, 2022. (Xinhua/Jiang Fan)

A herdsman hunts down caterpillar fungus on highlands with an altitude of 4,700 meters in Biru County of Nagqu, southwest China's Tibet Autonomous Region, May 26, 2022. (Xinhua/Jigme Dorje)