The speaker is sitting outdoors on an afternoon at summer's end, noticing a smell that seems left over from the morning. The images are odd and vivid: a burning hymnal, an excavation, fresh earth mixed with mildew and the "blood of cut roots." The scent is rich, a little unsettling, and slowly turning into heat.
The speaker admits to feeling unequipped. "If i were a dancer i would / know what to do" suggests a wish to respond to all this with the right kind of movement or expression. Instead there are only leaves, insects and warblers, which "seem to have / things under control." Nature doesn't need to be told how to act.
The ending is quiet and a bit self-mocking. The speaker settles for being "a better place holder," someone who simply holds a spot and pays attention. The mood is calm, humble and gently wry, with a sense that watching carefully may be enough.