But he also gained a lot. The mountain he patrols is known as the"heart of the 164-kilometer Lijiang River" and the "lifeblood" of the Guilin karst landscape, a world natural heritage site and tourism attraction.It gives him immense pride when he reflects on the fact that he is protecting the source of the mother river of about 5 million people.

Yang is a native of Guigang in Guangxi Zhuang autonomous region. After graduating from forestry school in July 1984, he was posted at the Maoershan police station, 430 kilometers from his hometown.

The police station is located in Tongren village of Huajiang Yao ethnic township, at the foot of the Maoershan Mountain. Every day, he and his colleagues patrol the mountain to protect the primitive forests.

The condition of the terrain he surveys can be judged from the fact that the ruins of a US bomber that crashed fighting the Japanese during World War II and the remains of its crew were found accidentally by two herbal collectors sometime in the late 1990s, about half a century later.

In the 1990s, with underdeveloped transportation and communication facilities, Yang and his colleagues scaled the mountain on foot. In his backpack, Yang carried a machete, some dry food, police gear and, most importantly, mosquito repellents. Some nights Yang spent in the mountains, with the ground as bed and a starry sky as quilt. Romantic as it might seem,the thick bushes in the forest are infested with poisonous snakes.