Fences may be symbols of personal separation in a negative sense, or protection in a positive one. These meanings are often derived from specifically who the fence is separating us from. If you can discern a feeling about what may happen if the fence were traversed (would it be better or worse), that may tell the role the fence is playing in the dream.
Fences can also be a source of boundary. This is true if there is a sense that the fence cannot be traversed.
What are the boundaries of your life in relationship to other characters in your dream? Perhaps you want to change those boundaries and move a relationship in a new direction. If you are alone at your fence, perhaps you need to or are protecting yourself from others more or excessively.