Do the leaves look brown?
No, the leaves are green.
    src        edge_attr  dst
0     1   to the left of    3
1     1   to the left of    2
2     1   to the left of    5
3     2  to the right of    1
4     2  to the right of   11
5     3   to the left of   15
6     3  to the right of    1
7     3  to the right of   11
8     5  to the right of    1
9     5   to the left of   10
10    5  to the right of   11
11   10  to the right of    5
12   11   to the left of    3
13   11   to the left of    5
14   11   to the left of    2
15   12               of    5
16   12  to the right of   14
17   13  to the right of   14
18   14   to the left of   12
19   14   to the left of   13
20   15               of    5
21   15  to the right of    3