Abstract:

To understand and master the historical hydrological change patterns and characteristics of the Da Hinggan Ling Mountains, a standardized chronology of tree annual rings width was constructed by Picea koraiensis. After analyzing the response relationships of chronology to hydrological and climatic factors such as temperature and runoff, it was found that runoff was the main controlling factor affecting the radial growth of Picea koraiensis, hence the historical runoff series of Gonger River drainage area from 1845 to 2016 were reconstructed using tree-ring width chronology. The reconstruction equations are accurate and reliable and can be used in the reconstruction of historical runoff. The reconstruction results showed that the runoff sequence of the Gonger drainage area showed an overall decreasing trend, with abrupt changes in 1849, 1854 and 1993, experienced a total of seven drying periods and six wetting periods in the last 172 years, there were two dry seasons (1853—1855 and 2000—2010) and three wet seasons (1869—1873, 1911—1918 and 1952—1958), the proportion of wet years and dry years was 17.4% and 10.5%. The reconstructed sequences have significant cycles of 3 a, 7-12 a, 15-22 a and 30 a, the hydroclimate of the study area is influenced by global large-scale activities. The wet and dry periods are generally consistent with the historical canonical records of natural disasters in the region, and correlate significantly with other reconstruction results in the vicinity. The innovation of this paper is to reconstruct the runoff variation characteristics of the southern Da Hinggan Ling Mountains in the last two centuries by using the precious tree species Picea koraiensis, which enriches the tree-ring database in this area and provides a reference for the study of hydrological changes in the region during long historical periods.

Key words: Picea koraiensis, tree-ring, runoff reconstruction, Da Hinggan Ling Mountains