Harvesting in the wasteland?

I am very early in the game, have not even gone to Diamond City, but I spent too many hours in the game already playing with settlement building. So far my main source of resources (wood and steel) have been loot, but it is becoming VERY frustrating to see trees and cars everywhere yet not being able to get wood or steel out of them because they happen to be behind the green wall… is there any way we can break down objects found outside the settlement? I know these are not the rarest of resources, but that artificial green line deciding what I can break down and what I can’t is really driving me nuts! I would not mind if it actually took some work to chop down a tree that is outside of the comfort of my settlement, so long as I was just able to do it...