What is growing on the trunk that looks brown?
The tree is growing on the trunk.
    src        edge_attr  dst
0     0  to the right of    7
1     0  to the right of    1
2     1   to the left of    0
3     1  to the right of    7
4     1  to the right of    2
5     1  to the right of    5
6     2   to the left of    1
7     2   to the left of    8
8     2   to the left of    4
9     2   to the left of    7
10    2   to the left of    6
11    4       growing on    0
12    4  to the right of    8
13    4  to the right of    2
14    4  to the right of    7
15    4  to the right of    5
16    5               on    7
17    5   to the left of    6
18    5   to the left of    4
19    5   to the left of    1
20    5   to the left of    7
21    6               on    7
22    6  to the right of    7
23    6  to the right of    8
24    6  to the right of    5
25    6  to the right of    2
26    7   to the left of    0
27    7   to the left of    6
28    7  to the right of    5
29    7  to the right of    2
30    7   to the left of    4
31    7   to the left of    1
32    8  to the right of    2
33    8   to the left of    4
34    8   to the left of    6
35    8               on    7