Canada/US border.

 oh really? So it just goes like that the whole way across? Must have been a pain in the ass to do that. So u crossed the border, did a ride and came back, who do u think u are? haha jk.

 Why do they cut the trees at the border? oO And why isn' the border at a comb or something?

 They cut a strip of trees at the border because it makes it easier to spot people trying to make an illegal crossing. It also gives a clear idea of the boundary of the two countries. In areas where attempts at illegal crossings are common, cameras, trip lines and drones are used protect the border.