Arboretum gardener Lhadun unlocked the huge black lock on the metal door, revealing a 300-square-metre nursery enclosed by the unwelcoming grey cement and stone walls.
This patch of Tibet Autonomous Region is home to less than 20 trees - the Pangong willow, Chinese tamarisk and Ramulus Myricariae.
They are more like bushes than trees, but still miraculous. The tallest are only a little more than 2 metres high. The youngest saplings are half as tall, thin and fragile, and braced by rusty supports.
Perched more than 4,500 metres above sea level, the town of Nagqu, capital of the Nagqu Prefecture, is a harsh environment for trees because of the extreme weather and permanently frozen earth.
While the top temperature has never exceeded 23 C, it can drop below minus 37 C in the depths of winter.
"These saplings have been here for eight years," Lhadun said. "Our gardeners and those from Zhejiang have tried everything possible. Almost 200,000 yuan (US$24,690) has been spent."
Long ago the local government of Nagqu offered a prize to anyone who could make trees survive.
Decades passed with the seemingly unattainable reward remaining little more than a dream, until Yan Yihua arrived in 1998.
The curious young forestry technician from Lishui, East China's Zhejiang Province, dispatched to Nagqu under the national Aid Tibet programme, heard about the challenge and made up his mind to plant trees despite the harsh conditions.
At its Third Conference on Tibet in 1994, the Central Committee of the Communist Party inaugurated the ambitious Aid Tibet programme. Besides a first batch of 62 infrastructure projects, worth 4.86 billion yuan (US$600 million) in total, competent officials and professionals were sent to serve on three-year terms as part of the scheme.
Zhejiang and Liaoning Provinces were paired up with Nagqu. Yan Yihua was a member of the second team from Zhejiang.
"They had tried but failed," Yan said. "I made it because I found out the true reason.
"I thought it was not the low temperature. Otherwise there would not have been trees in the north of Heilongjiang where it could be a lot colder in winter.
"It was actually because of dehydration in the dry winds. So as long as the trees can get proper protection from the winds and develop a stronger root system, they would survive," Yan declared.
Yan decided to select and try saplings growing at the highest possible altitudes, seeing that previous attempts were brought from Lhasa which is 1,000 metres lower.
With local colleagues he tried to transplant various trees from Ngari and Lhoka.
To protect the saplings from the freezing wind they erected metal supports, wrapped the saplings in hay and thickened the surface layer of soil in the winter.
"I even brought root enhancement chemicals from my hometown," he recalled.
Among the more than 10,000 trees transplanted by the time Yan finished his three-year service in Nagqu, more than 200 survived, thanks to their meticulous care.
Yan and his successors, sent by Zhejiang and Liaoning Provinces, as well as five major State firms under the same Aid Tibet programme, which has entered its 11th year and fourth stage, have created plenty of miracles like the trees in Nagqu.
The unprecedented assistance gave Tibet an immediate facelift. From Lhasa to the prefectures, public facilities for agriculture, animal husbandry, transport and communications, education and medical services received substantial upgrades.
"Such changes would have been unimaginable were it not for the forceful push from the aid packages," said Cao Bianjiang, head of Lhasa's Committee for Development and Reform.
Pledged assistance ballooned in 2001 at the Fourth Conference on Tibet. The central authorities promised a 31.2 billion yuan (US$3.86 billion) package covering 117 projects. The provinces offered 1.06 billion yuan (US$131 million) for another 70 projects. The actual figures may be substantially larger.
Nagqu alone will receive more than 206 million yuan (US$25.5 million) - 133 million yuan (US$16.5 million) from Zhejiang and 73 million (US$9 million) from Liaoning - which does not take into account offers from five State firms, including the prosperous China National Petroleum Corporation, China Petroleum & Chemical Corporation, and China National Offshore Oil Corporation.
As in Lhasa, outside assistance can be found behind almost every sign of change in Nagqu.
Before 1985, Nagqu was a small, desolate town with one restaurant, according to Duan Xiangzheng, commissioner of the prefecture.
Today, Nagqu takes visitors by surprise with its size and modern look.
The two main streets, respectively built by and named after Liaoning and Zhejiang provinces, meet at right angles at the heart of the transport hub of northern Tibet. Along them, alongside shops and stalls selling Tibetan-style furniture, costumes, jewellery and groceries, there are Internet cafes and bars that serve sweet tea, a favourite among Tibetans.
"It is fair to say the past decade has witnessed the most rapid development in the history of Nagqu," said Li Liangfu, who heads the 46-member Zhejiang team, the fourth, dispatched to Nagqu last year.
The Zhejiang native is now a deputy secretary of Nagqu's Party Committee. His province is behind projects including the 5-million-kilowatt, 100-million-yuan (US$12 million) Jaggang power station in Xainza County, the prefecture hospital's emergency centre, and schools in the counties.
Driving on the Lhasa-Nagqu section of the Qinghai-Tibet Highway, one could hardly miss the conspicuous signs for Hangzhou Village and Jiaxing Village on the walls of a small settlement. These are houses built with money from Hangzhou and Jiaxing, two cities in Zhejiang Province.
From the first hydropower station in Nyainrong County to the first kindergarten in Sog, and to the very building where his own office is located, Chen Chunsheng, a deputy commissioner of Nagqu and leader of the fourth Liaoning team, appeared to be enumerating his family's most valued possessions.
Unlike in the past when assistance was focused primarily on infrastructure upgrades, more and more money is being put into projects delivering immediate benefits to the average farmer and herdsman, according to Chen.
The first 34 projects Liaoning selected for his term of service feature a heavy emphasis on medical care, education, and residential housing.
"There had never been formal pre-school teaching in Sog before the city of Dalian built a kindergarten there," Chen said. "The city also built a primary school, thoroughly renovated the county's secondary school, financed a radio and television broadcast centre, as well as Tibetan houses for the local residents."
Liaoning Province has decided to appropriate more than 10 million yuan previously earmarked for a building materials test centre so as to provide solar power units, satellite signal receivers and TVs.
"Each of the Bachen, Amdo and Sog counties will receive 200 sets, worth more than 20,000 yuan (US$2,470) each," he said.
In the Xomong Township with a population of 6,000, a recipient of Zhejiang Province's Thousand-Household Illumination Project, home solar and wind power generators have transformed the lives of the nomad population.
"Now we can not only hear, but see what is happening in places far away," said Jampa, head of the township.
Right behind the spacious courtyard of the township government building, where there are three windmills, the plates of solar power units glitter on flat roofs of Tibetan houses.
"We still have more than 1,000 families who have no access to electricity," Jampa said. "We need further assistance."
He is optimistic about being granted a larger aid package because help is received not only from the autonomous region but from Zhejiang Province and the State Development and Reform Commission.
Thousands of kilometres away in Lishui, Zhejiang Province, Yan Yihua, who is now a deputy chief of the city's Forestry Bureau, is still concerned about the trees in Lhadun's custody.
"I visited Nagqu in July," he said. "I would help them expand the project, if I had the resources."
(China Daily September 23, 2005)