What does Groot's last line mean in The Guardians of the Galaxy (movie)?

Question

Toward the end of The Guardians of the Galaxy

when the Dark Aster is about to crash, Groot begins enfolding the rest of the team in a protective, multi-layered cocoon of branches and vines, presumably to cushion them against the impact. When Rocket tearfully asks why he's sacrificing himself for the rest of the team, Groot slowly says, "We are Groot."

Since this is very distinct and different from the rest of his dialogue, no one needs to translate it as Rocket did a few times with his other lines.

But the exact meaning of the line is a bit unclear. Has anyone involved in the production of the movie said anything about what that line means and why he said it that way?

Answer 1

You'll find different iterations of the same interpretation around the web, but the one I liked best was from the Mennonite World Review (archive):

"Groot no longer sees himself as an individual. The lives of his friends are now enfolded into his own. The well-being of each of them is not only equivalent to but above his own because this family is now his identity."

Groot enfolds the group around himself, itself a symbol of their joined identity. The imagery of a connected group comes up again when they all join hands when holding the infinity stone, a task that could not be taken on alone.