Is the fence behind the trees?
No, the fence is in front of the trees.
    src        edge_attr  dst
0     0               by   23
1     0      in front of   12
2     0      in front of    1
3     1               on   17
4     1           behind    0
..  ...              ...  ...
82   20  to the right of   13
83   21  to the right of    6
84   24               in   23
85   24               of    6
86   25               in   23

[87 rows x 3 columns]