Did you know the forests connecting the US to Candada do not touch?

You heard that right… border of between the United States and Canada is a longest continually clear cut stretch of land in the world. It is maintained by these guys, Canada & United States Border | International Boundary Commission, the International Boundary Commission and they take their job very seriously.

Does anyone know the logic behind this. Does this have anything to do with logging and protecting natural assets of forests on each side of this border?