Photo shows Yunnan Snub-nosed monkey that inhabits within China’s southwest natural forest transect zone. (PHOTO: XINHUA)

By LIN Yuchen

The currently established natural forest transect zone in China’s southwest forest region has been an effective area in biological research. According to the Chinese Academy of Forestry (CAF), the transect in this area now contains 44 sample plots of one hectare in size that cover 12 forest types and are inhabited by several key wildlife species under national protection, like Asian elephants and Yunnan snub-nosed monkeys. In addition, based on incomplete statistics, there have been 969 species of woody plants, totaling 143,800 plants, that lie within this established transect.

The southwestern forest area is the largest natural forest area of China and also key to a functioning ecology. As part of the country's major ecological projects, the natural forest protection project and the systematic construction project for protective forests along the Yangtze River Basin area operate here. Improving the quality of the forest ecological environment in the southwestern forest area serves an irreplaceable role in promoting the construction of an environmentally friendly China.

Rich in plant species

With a large altitude span that extends from 650 meters to 4,300 meters above sea level, the forest plant species of the southwestern transect are well represented. It includes more than 10 types of forest such as tropical rain forest, monsoon evergreen broad-leaved forest, cold-temperate coniferous forest, and dry-heat sparse-tree shrubs and grasses.

"Here, the tropical rainforest includes three types such as Shorea wangtianshuea forest, Terminalia myriocarpa, and Pometia pinnata forest; the broad-leaved evergreen forest includes five types; and the coniferous forest includes seven types of forests,” said Li Shuaifeng, researcher of the Institute of Highland Forest Science at CAF.

Li also added that there are also mixed evergreen and deciduous broad-leaf forests dominated by Fagus, cold-temperate scrub dominated by Rhododendron pingianum, and dry-heat rare-tree shrubs and grasses such as Terminalia franchetii.

Various survey objects

It is understood that the researchers investigated plant richness, functional, phylogenetic and soil microbial diversity before deciding to construct the southwestern transect.

"We obtained a total of 5,550 soil samples and 969 species of plant functional trait indicators, along with 88 soil profiles in the southwestern transect. Thirteen ecosystem functional indicators of four types, including carbon storage, soil nutrients, decomposition and maximum water holding capacity, had been collected,” said Li.

The dynamic monitoring sample plots in the southwestern transect also include wildlife under key national protection endeavors.

"At present, a total of 45 kinds of national key protection wild plants have been found in the transect, among which there are four kinds of wild plants under national level-I protection; and 41 kinds of wild plants under national level-II protection, like Alsophila costularis and so on,” said Li.

Meanwhile, the transect zone involves the habitats of Asian elephants, Yunnan golden monkeys, baiyaji chickadees, as well as Qian golden monkeys. All of them have been rare wild animals that have been protected a long time ago.

"In the future, we will conduct surveys and monitoring on a cyclical basis, with surveys every five years; on top of the existing arrangements, we also plan to add animal and microclimate monitoring, combining infrared cameras and small weather stations to monitor animal diversity and meteorological factors such as temperature, precipitation, and humidity in the sample site," said Su, adding that the monitoring of the southwestern transect is proposed to last more than 30 years.

High standard construction

It took Su Jianrong, director of the Institute of Highland Forest Science at CAF, along with his team many years to construct this transect. "The establishment of ecosystem function sample zones like this can systematically monitor the overall pattern of ecosystem function changes, and reveal the mechanism of how an ecosystem functions."

"In order to ensure the long-term continuity of dynamic monitoring and long-term research on the samples collected in the transect, our institute has signed a 30-year agreement with 10 organizations for the co-building of dynamic monitoring samples," added Su.

The construction of the southwestern natural forest transect has high standards. These are in accordance with the national forest ecological positioning research station sample construction standards, drawing the technical specifications of the Smithsonian Tropical Research Institute Tropical Forest Science Research Center of the U.S. as references.

The transect’s construction draws on a satellite positioning system to determine such elements as the slope, slope direction, concavity and elevation of the sample plots. Every 20 meters the transect builders installed fixed stakes in cement piles; and all woody plants whose diameter at breast height was greater than 1 cm were marked for positioning survey, which records their species name, height, exact coordinates.