What are the trees in front of?
The trees are in front of the sign.
    src        edge_attr  dst
0     1               in    2
1     1             near    5
2     2      in front of    4
3     2           around    5
4     2      in front of    3
5     2      in front of    6
6     3            above    5
7     3      in front of   11
8     3  to the right of    6
9     3           behind    5
10    4           behind    5
11    4             near    6
12    4   to the left of    8
13    5      in front of    4
14    5         lying in    2
15    5      in front of    3
16    5               in    2
17    5             near    1
18    5            under    3
19    6             near    4
20    6   to the left of   11
21    6   to the left of    3
22    7  to the right of    9
23    8  to the right of    4
24    8  to the right of    9
25    9   to the left of    7
26    9   to the left of    8
27   11  to the right of    6
28   11           behind    3