China News Service, Beijing, June 22 (Reporter Sun Zifa) The Qinghai-Tibet Plateau Research Institute of the Chinese Academy of Sciences announced on the 22nd that the researcher Liang Eryuan of the ecosystem pattern and process team of the Institute in the Namco District of the Qinghai-Tibet Plateau has established a time span of 537 years ( 1479-2015) chronology of shrub ring width.
This is the longest shrub ring width chronology in China to date, which can reveal the dry and wet climate change in spring in the Namco region of the Qinghai-Tibet Plateau, and also provide natural archives data for the long-term climate change in the high mountain area of the central and southern Tibetan Plateau. This important research achievement paper in the field of the Tibetan Plateau Ecosystem has recently been published in the international professional academic journal Geophysical Research Letters.
Lu Xiaoming, the first author of the research paper and a postdoctoral fellow at the Qinghai-Tibet Plateau of the Chinese Academy of Sciences, introduced that tree rings can understand the past climate change and forest dynamics of the Tibetan Plateau. However, because the forests on the Tibetan Plateau are mainly distributed in the eastern, southeastern and southern slopes of the Himalayas, it is difficult to carry out tree-ring studies in the interior of the Tibetan Plateau, and the shrubs are more widely distributed on the Tibetan Plateau. The only way for the main tree ring network to reach the interior of the plateau.
Namtso is located in the transition zone between the west wind and the monsoon on the Qinghai-Tibet Plateau, and belongs to the area of alpine desert vegetation. The cedar shrubs are distributed on the sunny slope at an altitude of 4740 meters to 4920 meters. In extremely cold and arid environments, cedar shrubs grow slowly, with an average annual ring width of about 0.3 mm. However, it was not clear to the academic community whether the rings of cedar shrubs, like tree rings, indicate changes in the living environment over the past few hundred years.
To this end, the scientific research team of the Institute of Tibetan Plateau Research of the Chinese Academy of Sciences conducted a field investigation around the cedar shrubs around Namco and found dead cedar plants and some residual stems. By cross-dating with the living cypress shrub ring series, the scientific research team successfully established the shrub ring width chronology from 1479 to 2015, spanning 537 years, and has become the longest shrub ring width chronology in China.
Based on a reliable sample size, the research team also cooperated with Professor Zhang Baoqing of Lanzhou University to reconstruct the dry and wet climate changes in the spring of 406 years (1605-2010) in the Namco region. The reconstructed variable is the drought index-standardized water anomaly index. The index system takes into account all factors affecting the drought such as precipitation, snowfall, snow water equivalent, evapotranspiration, soil moisture and runoff in alpine regions.
Researcher Liang Eryuan, the corresponding author of the research paper, said, "We found that the growth of high-altitude cedar shrubs is limited by the water conditions in the early growing season, and high temperatures will exacerbate water stress, which is not conducive to the growth of cedar." At the same time, the latest research found that the Namco area experienced two longer periods of drought, 1637–1683 and 1708–1785, indicating that extreme cold conditions during the Little Ice Age may lead to a reduction in the water cycle, which in turn may cause drought. (Finish)