Figure 5. Mean Sassafras albidum first-order root carbon δ¹³C values.

Roots were at least two weeks old at the time of whole tree labeling in 2009. Black bars represent roots that were sampled immediately prior to whole-tree labeling. Light grey bars represent roots sampled after whole-tree labeling. Note that less negative values indicate greater isotopic enrichment. Error bars denote standard error. Different lower case letters denote significant differences at P≤0.05 using a one tailed T-test between pre- and post-labeled roots of each tissue type.