树轮密度和宽度在气候变化敏感区域对过去气候的指示

Tree-ring data have been playing an very important role in studing past climate change. In this project, tree ring samples were collected from 4 climate-sensitive forest sites in high latitude, high altitude, lower forest limit in semi-arid region and forest-steppe ectone. Seven tree-ring parameter, i.e. maximum density, minimum density, mean earlywood density, mean latewood density, tree-ring width, earlywood width and latewood width were obtained using densitometry method and their standard chronologies were established. The chronological characteristics were evaluated such as interseries correlation and the agreement with population chronology. Furthermore, the correlation analyses were performed between seven tree-ring parameters and climate elements. Finally, the past climate was reconstructed using tree-ring density and width, and the characteristics of the reconstructed series were analyzed. The main results are summarized as follows: 1). The maximum density should be used as the parameter for ring dating in high latitude and high altitude regions, while in semi-arid region ring-widths produce the best dating results. 2). The ring-width series are of age-related growth trend, and ring density series were seldom effected by growth trend. 3). Tree ring density can provide more temperature-related information in growing season not only in high latitude and high altitude regions but also in semi-arid regions. Tree-ring width was a better indicator to previous winter temperature as well as precipitation. 4). Low frequency variationas in winter temperature during the last 200 years in Changdu are rather similar to that in Chuanxi. 5). The low Solar activity period corresponded with the low-temperature one in high altitude region. 6). The reconstructed temperature series displayed 50-60 a, 4 a and 2 a periods in high altitude region.This study showed the potential of tree-ring density in temperature reconstruction in China.

在我国高纬度、高海拔区域建立树轮密度和宽度序列；分析树木生长与气候要素的关系，从而确定树轮变量所记录的气候信号；利用所建的树轮序列和所确定的树木－气候关系，重建研究区过去百年至千年尺度的气候变化史实；分析重建气候变化趋势及规律以及太阳活动和火山爆发与气候变化关系；为全球变化研究提供高分辨率基础数据和填补国内研究的空白。