The speaker compares themselves to a tree without leaves, and the whole poem grows out of that image of feeling bare and overlooked. They say no one appreciates them, that they're too scared to "make my own food" even though photosynthesis is possible, and that they've been in the dark so long no one noticed them. The science language is a clever way of talking about confidence: the tree has the means to live and give, but fear holds it back.
There's a small, quiet turn in the middle. The speaker tries to give oxygen to others, yet feels they barely contribute. Then comes the wind, which they couldn't feel but which was "always with me," a hint that support may have been present all along, even if unnoticed. Still, the poem ends bleakly: "I think I'd better be cut." The mood is lonely, self-critical and sad, with a fragile trace of hope that the speaker can't quite believe in.