Lai Zhenglin, a 43-year-old farmer living in east China's Zhejiang Province, is proud of his new skill, which is identifying trees.

Lai, with a primary school education, can identify more than 200 tree species in his hometown, Gutianshan Nature Reserve.

By observing the tree leaves and touching the bark, Lai can tell the tree's local name, scientific name, and even the Latin name.

Lai used to go to other cities to work as a welder. But after trained by scientists in 2005, he stayed in the nature reserve to help with their forest survey and study on the co-relation of forest and climate change.

Lai's job now is going to the mountains to identify the tree species, measuring their chest perimeter and recording their locations.

"We will record and measure every single tree on the mountains," Lai said.

The research dated back to 2004, when scientists with the Institute of Botany under the Chinese Academy of Sciences marked out a sample site of 24 hectares in the Gutianshan Nature Reserve to study the ecosystem. The nature reserve is home to abundant species. Among them, are over 1,400 species of seed plants.

Priorities for the research have gone beyond biodiversity and ecology, and extended to the hot topic of climate change.

Earthwatch Institute, an international non-governmental organization, joined the research and set up the China Regional Climate Center in Gutianshan in late September, with funding poured in from the Hong Kong and Shanghai Banking Corporation (HSBC) as part of its climate partnership program.

The center will serve as a valuable platform for developing more extensive and detailed forest dynamics monitoring and examining human beings' disturbance in the face of climate change, according to Pei Kequan, director of China Regional Climate Center.

"We choose this place because it's unique. Such a large area of sub-tropical ecosystem can only be found in this place," said Pei.

"Previous studies had been focused on tropical ecosystems. We lack the data about sub-tropical ecosystem. So we need to collect data here in Gutianshan for research," Pei explained.

Forestation is believed to improve the environment as a major carbon sink. Forests, which account for about one third of global landmass, can absorb carbon dioxide and slow down the pace of global warming effectively. From 1980 to 2005, the forests in China have absorbed more than 5 billion tons of carbon, mitigating climate change to a great extent.

But for scientists, there are still many unknown elements about the interactions between forest and climate change.

"Trees absorb carbon dioxide and release oxygen in photosynthesis, but they also emit carbon dioxide during respiration. Fallen leaves, branches and roots also release carbon dioxide. We are still not clear about the net carbon storage capacity of trees," Pei said.

"Besides, how forests, especially those in sub-tropical regions, react to climate change is still unknown. So we need to conduct research to this effect," Pei added.

Measuring and recording all the 140,000 trees within the sample area in the Gutianshan Nature Reserve is a tedious work. Scientists have to get help from volunteers and local farmers.

Lai is paid 50 yuan (7.35 U.S. dollars) every day for his efforts, not as much as a welder in big cities. Although more than 30 farmers were recruited for the job at the beginning, now only six have stayed.

"I think this work is fun. I like it very much. I like identifying the plants that other people don't know." Lai said he had measured and recorded more than 50,000 trees. Researchers will use the data accumulated over the course of five years to evaluate the change of trees' carbon storage capacity.

"Scientists taught me about many interesting trees. For example, a kind of tree is ticklish. If I scratch its trunk, the end of its branch would sway. Scientists told me its name is stewartia."

"One tree bears chicken-foot-shaped fruit, which is sweet and sour, to girls' liking. Scientists call it hairyfruit turnjujube," Lai said. He always takes with him a list of plant names in both Chinese and English.

"Some trees look the same. But if you observe their leaves and branches very carefully, you will find the difference."

Climate change is a subject for scientists and environmentalists. Lai doesn't know the just-concluded Copenhagen conference on climate change, but he has felt the changing of climate since a long time ago.

"The first time I heard the term 'climate change' was when volunteers from HSBC came to Gutianshan earlier this year. I don't know whether climate change has anything to do with my life."

"But I remember when I was young, about 20 years ago, the pond in front of our village would freeze in winter. I could walk on the thick ice. But now the ice is hardly seen. Winter is not as cold as before."

Lai said he even felt the weather doesn't tally with traditional Chinese calendar, which guides agricultural activities.

Some extreme weather also hit that area, making it hard for Lai to understand.

Pointing at a fallen tree on the hill, Lai said many trees were fractured during the snowstorm at the beginning of 2008. "There are more broken trees on the top of the mountain. The snow of that year was too heavy."

"I feel the air these years are not as good as before. And some dirty things can be found on tree leaves, which I had never seen before."

Lai said his new job has changed him a lot. "I used to cut trees -- any tree -- for firewood. After doing this job, I know may trees are very precious, and should not be cut. I will never cut those trees. And I also tell others not to cut."

Every family in Lai's village, with a population of more than 700, burns wood for cooking.

"My family burns several thousand kilograms of firewood every year. Now we cut bushes instead of big trees," Lai said.

Although Lai's income is not as much as before, his wife is happy that he doesn't have to work in big cities far away. "Whatever he likes I will support."

Lai's 15-year-old son also likes trees. "Our teacher told us at science class that trees can help keep out typhoon."

Through the help of farmers and volunteers like Lai, scientists hope to find the interactions between forest and climate, and offer their advice to decision-makers on forest management and how to protect the ecosystem.