For 27-year-old P. simoniir, the reducing sugar content in phloem and xylem at different heights did not show significant difference, while it showed closely negative correlation with the ratio of damaged trees.

• 在27年生同一品系小叶杨树中，虽然不同高度的还原糖含量差异不显著，却与被害株率呈现紧密负相关。