北京西山老龄树记载的森林干扰历史

张启, 程雪寒, 王树芝

History of forest disturbance recorded by old trees in Xishan Mountain, Beijing

ZHANG Qi, CHENG Xue-Han, WANG Shu-Zhi

图4 北京西山老龄树标准化年表与区域气候要素相关关系。P, 降水量; PDSI, 帕尔默干旱指数; T, 平均气温。横坐标中字母“p”和“c”分别代表前一年和当年; 虚线和实线表示相关分析的95% (p < 0.05)和99% (p < 0.01)显著性水平线。

Fig. 4 Correlation coefficients between the standard tree-ring chronology of sampled old trees and climatic factors in Xishan Mountain, Beijing. P, precipitation; PDSI, Palmer drought severity index; T, mean air temperature. “p” and “c” before the numbers at the x-axis represent the month of previous year and current year, respectively. Horizontal dashed and solid lines represent Bonferroni-corrected p levels of 0.05 and 0.01.