Response of earlywood and latewood ring width of Cryptomeria japonica to climate change in Lushan Mountain, eastern China

  Objective  This paper aims to study the correlations between earlywood width, latewood width of Cryptomeria japonica and temperature as well as precipitation in Lushan Mountain of eastern China, so as to reveal the response of radial growth of C. japonica to climate, to understand the impact of climate change on forest ecosystem in this area, and to provide evidence for the protection of C. japonica and the selection of afforestation area under the condition of climate change in the future.

  Method  Studying the main distribution of forest coniferous species, C. japonica in the Lushan Nature Reserve, the tree core samples of C. japonica were sampled and treated by dendrography, and the standard chronology of earlywood and latewood was established. Correlation analysis of climatic factors in Lushan area with the tree-ring standard chronology was taken.

  Result  (1) All the statistical characteristics of the earlywood chronology were better than the latewood chronology. Compared with the radial growth of the latewood, the radial growth of the earlywood was more sensitive to the change of the monthly mean temperature. (2) The average annual temperature and annual precipitation in this area showed a significant increasing trend, the average temperature in each month showed an upward trend except August. (3) The radial growth of the C. japonica was mainly affected by the temperature, the lag effect of temperature on the growth of earlywood was particularly obvious. High temperature in summer (July) not only hindered the growth of ring width of earlywood in that year, but also affected the formation of earlywood in the next growing season. The increase of precipitation in growing season (April to July) was beneficial to the formation of earlywood and latewood in the growing season.

  Conclusion  The changes of temperature and precipitation in different seasons affect the formation and growth of the earlywood and latewood. Under the background of future climate warming, the C. japonica forest in Lushan area may appear the phenomenon of growth decline.