What's on the tree?
The trunk is on the tree.
     src        edge_attr  dst
0      0   to the left of   16
1      0  to the right of   13
2      0  to the right of   26
3      0   to the left of   19
4      2   to the left of    4
..   ...              ...  ...
104   26   to the left of   16
105   26  to the right of   13
106   26   to the left of   21
107   26   to the left of   19
108   26               of   16

[109 rows x 3 columns]