Xu Fengxiang (in red) makes a field research in the Gangxiang Spruce Forest in the 1980s. [Photo provided to chinadaily.com.cn]

In the following 18 years until her retirement, Xu's footprints have covered 130,000 km and more than 20 virgin forests in Tibet for field research. She visited the base camp at Qomolangma, the world's highest mountain known in the West as Mount Everest, three times, respectively, aged 61, 70 and 78.

Located in Lynchi's Bome county, the Gangxiang Spruce Forest has an area of 46 sq km with more than 61 percent covered by spruce trees.

Without Xu's 7-year field survey in the 1980s, this forest would not have been measured and set as a nature reserve for protection. It was ranked by China National Geography Magazine as one of "Top 10 Most Beautiful Forests" in China in 2005.

"She is China's Jane Goodall," said Yang Ling, an environmentalist living in Beijing.

"Like Goodall who contributed her life to the study of wild chimpanzees and the environmental cause, Xu spent more than 60 years on the ecological study with the latter half of her career specializing in Tibetan ecology and helping establish a number of nature reserves."

In the past dozens of years, the ecologist has published eleven academic books introducing the distributions of wild flowers, mountains, valleys, rivers and forests in Tibet.

Xu Fengxiang makes a field research on the Yarlung Zangbo River in the 1980s. [Photo provided to chinadaily.com.cn]

Sitting in a room at the ecology institute she founded, Xu said it would be her last visit to Tibet, where the lack of oxygen due to higher elevations may be harmful to her health as a senior.

"It is really too hard to say goodbye," said Xu, with tears welling up in her eyes.

"I bid farewell to the plateau many times since my retirement in 1995, but I flew back from Beijing again and again for the love of nature and this beautiful land in China."

Xu said she is currently working on publicizing ecological knowledge about Tibet and raising the awareness of protecting nature among the youth.

"I gave lectures to students about ten times a year and introduce them to the Tibetan plant species," she said.

"I'm glad to become a scientific preacher for Tibet till my death and a preacher encouraging man to protect our plateau species."