Cycad National Nature Reserve in Panzhihua, Sichuan province protects more than 385,000 of the ancient tree species in the only State-level nature reserve for their protection.

Known as living fossils, the cycads in Panzhihua are the world's oldest seed plants and have existed for between 200 million to 300 million years. Often confused with palm trees, they have a woody trunk and evergreen leaves.

The nature reserve was established in 1983, but the plants remained threatened by a limestone mine that continued to be operated by Pangang Group Mining for 35 years despite efforts by the reserve to close it.

According to Xu Huakui, head of the limestone mine, the flux limestone produced there was an indispensable auxiliary raw material for the metallurgical production of Pangang's blast furnace, and more than half of Pangang's flux limestone used every year was supplied by the mine.

Thanks to the intensification of environmental protection in the country, the concept of "lucid water and lush mountains are invaluable assets" was accepted by the general public.

In 2017, Panzhihua decided to close the limestone mine although it meant a loss of 680 million yuan ($99 million) to Pangang.

The Panzhihua committee of the Communist Party of China and the Panzhihua government established a coordination mechanism with Pangang to promote the closure of the limestone mine and the ecological restoration of the mining area.

In 2017, Pangang invested 5.3 million yuan to complete the ecological restoration of 4.8 hectares of the mining area.

In October 2018, all limestone mining in the reserve stopped and the ecological restoration of the limestone mining area was completed in October 2019, according to Li Chunfeng, an official with the publicity department of Panzhihua.

From 2017 to October 2019, 23 drought-tolerant and hardy tree species, such as rock persimmon, which are suitable for the local climate and environment, were planted in the former limestone mining area.

"A total of 12,000 trees and 370,000 shrubs were planted, and their survival rate has reached more than 95 percent," Li said.

Ning Guangxia contributed to this story.