摘要
研究了祁连山中部不同海拔高度青海云杉的树轮宽度对气候因子的响应，重建了祁连山中部 ２３０ ａ以来春季３～５月的降水和 １７０ ａ以来夏季６～８月的气温序列。结果分析发现，不同高度的云杉树轮生长对春季降水极为敏感，呈现显著正相关；对夏季气温的响应程度，各海拔高度却不相同，夏季气温对上、下限云杉生长有显著影响，但对于森林中部云杉作用并不明显，总体表现为负相关，夏季高温对树木生长不利。气候重建结果发现，祁连山中部的春季２３０ ａ以来经历了大幅度长阶段的干湿变化，存在明显的 ６９ ａ和 ２１ａ周期；１７０ ａ以来夏季气温变化频繁，存在明显的２～４ａ周期。目前，祁连山中部正处于相对干旱和温暖时期，呈现出向暖干方向发展的趋势。
Using tree-ring width chronology of Picea crassifolia in the middle region of Qilianshan Mountains, we studied the relationship between tree-ring and climate factors, and reconstructed spring precipitation and summer temperature in the middle region of Qilianshan Mountains. The results indicated that the tree-ring width is sensitive to spring precipitation, and summer temperature has influence of different degree on trees of different altitudes. High temperature of summer is harm to tree growth. There is positive correlation between tree-ring width and spring precipitation. In spring, the rainy season has yet not arrived, and precipitation is deficient. The soil water becomes the limited factor to tree-ring growth. Little precipitation leads to the shortage of soil water, so the tree-ring width is narrow. Summer temperature has negative influence on the growth of tree^ring. In summer, monsoon brings precipitation to the middle region of Qilianshan Mountains. In general, the tree is satisfied with the water situation, but high temperature results in intense evaporation. By influencing soil water, summer temperature limits tree-ring growth. So high temperature of summer corresponds to the narrow tree-ring. But summer temperature cannot limit the tree growth in middle altitude. Because, in summer, the altitude of maximum precipitation in Qilianshan Mountains is just at 2 700-2 800 m. Enough rain reduces the negative effect that high temperature imposes on the tree growth. The reconstructed spring precipitation had the periods of 69- and 21-year, and it indicated that the middle region of Qilianshan Mountains was mainly in a humid state since A. D. 1770. Summer temperature had 2-year to 4-year periods. Now, this area is dry and warm, and it shows the warmer and drier tendency.
出处
《中国沙漠》
CSCD
北大核心
2001年第2期135-140,共6页
Journal of Desert Research
基金
国家自然科学基金项目(49731010)
国家重点研究发展规划项目(G1999043501)
