There are a couple different ways that the song Evergreen by Switchfoot can be interpreted.The biggest clue as to how this song should be interpreted are the words “I want to live all year around,” and the association with the types of trees that stay green all year around.
One way that the song can be interpreted, the way I took it before doing some research, is that the speaker wants to live his life for Christ all year around. He doesn’t want to do this thing Christians so often do where they go to an event or experience a holiday “high” then live for Christ. After the “high” wears off, they go back to living the life they’ve always lived. In that way, they are like trees that lose their leaves when the difficult times come. What I took the speaker to be saying is that he wants to be keep his leaves all year and not step away from Christ when things get hard, or even, go back to normal.
After I did some research, I found some people who thought the song was less about living for Christ and more about living to make a difference in general. It has the same concept as the interpretation above just a little bit of a different focus.
What remains constant through the two interpretations is that the speaker does not want to just experience the holidays then go back to living the life he once lived, he wants to live the life he lived during the holidays all year.