What's with these boxes?

In the forest that's in the south-eastern section of the town, there are three things that look like cardboard boxes. But my mayor can't interact with them at all -- she can't open them or pick them up or anything.

Why are they there, and am I supposed to do something with them?

Thanks!

To properly interact with those boxes, you need to use

Ah, thank you! I don't use tools on boxes in real life, but I guess I need to think more game-like. :-)

Well, you would not succeed trying to break-open those boxes with your raw hands anyway.
No problem

And what's with that boulder near to the boxes?