*3.4. Relationship Between* δ*15N and* δ*13C in P. crassifolia Leaves*

Relationship between the δ13C and δ15N values of all leaf ages pooled was significantly positive for *P. crassifolia* samples (*p* < 0.001, Figure 5). The correlation coefficient between them was 0.44. Different leaf ages (range from current-year leaves to 3-year-old leaves) were represented by triangles, squares, circles, and rhombuses, respectively.

**Figure 5.** Relationship between leaf δ13C and δ15N values of *P*. *crassifolia*. Leaf ages (current year leaves: triangles; 1-year-old leaves: squares; 2-year-old leaves: circle; 3-year-old leaves: rhombic) are also given.

#### **4. Discussion**
