I've been trying to remember this anime for ages so I'm hoping someone here knows it. It was a movie about a boy that found a girl during a human war against nature, she basically taught him the war was wrong, and then he put his life on the line to stop the war. Generic as heck, I know. I mainly remember the male lead could kinda turn his body into a tree, I think he was something like the world's protector? The world was post apocalyptic with advanced technology like weaponry (big fancy guns and possibly a mecha-ish suit thing), and I believe the final fight happened by some giant train tracks? It was on Netflix like 5 years ago so it probably came out around 2010. It probably wasn't that popular. This is a long shot, but I'll be eternally grateful if someone else remembers it! Note: I may have confused part of the movie with Castle in the Sky...
All i remember about that move is near the end they come out from a moving volcanoe, and the guys friend sees him from like 10+ miles away and goes, hey look there he is. Guy had elf eyes i swear. Sorry but i forget the name of the movie