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2 北京西山老龄树树轮宽度、标准化年表和树木生长变化率。灰线表示树木个体, 黑线表示不同个体的均值。

Fig. 2 Tree ring width, tree ring width index and percentage growth change of sampled old trees in Xishan Mountain, Beijing. The grey line represents individual trees and the black line shows the mean of different trees.