It’s the same tree from Gun’s flashback with his father, around which he and his father had shared precious memories and happy times. But more importantly, it’s where his father had buried a box filled with keepsakes, including a pair of cufflinks Gun would only get to wear when he was an adult, and a signed baseball little Gun got from the first game he ever went to with his dad.
But Gun hadn’t understood at the time that they wouldn’t revisit the tree again, since he hadn’t known about his father’s illness. “Gun, listen to me carefully. Right now and from now on, whenever you feel scared, be like Daddy.” Dad laughs his trademark laugh, now Gun’s. “Laugh like this, okay? If you do, I’ll always be with you to protect you.”
In the present, Gun digs up the keepsake box, and cry-laughs when he pulls out the baseball first, then the cufflinks. After he puts them on, he reads a note left by his father for when he’d inevitably find it as an adult: