The expression "that tree is far away" is used in situations to express that the last statement made by that speaker is irrelevant and unimportant information that can be ignored, rather than repeated. It's best used as a reply when a person mumbles something, an accompanying individual cannot
understand and asks for them to re-say their last line, only to be told "that tree is far away," indicating that what they originally spoke was not worth repeating.
It's derived from a Mitch Hedberg comedy act:
"I mumble a lot on stage, I'm a mumblerer. But sometimes what I mumble is some
insignificant shit. Like I'll be walking
down the street with my friend, and I will have said something, but he didn't hear me, so he says "What!?" SO I'll say it again, and again he had not heard me, so he'd say, "What!?" And now by this time I am yelling "That tree is very far away!"