Jackarandajam
Maester
The highwayman was first published in 1906, at the time gusty was probably an acceptable way to describe something affected by wind rather then something wind does, more like "gusted" maybe. Also in the context of the first few lines of the poem, the word doesn't grate as much. Also gusted would sound past tense and detract from the immediacy of the piece.
Also, it both isn't melodramatic ("clawing" trees, for instance; this is a high-adventure poem, not Poe) and doesn't detract from the mood ("wind-blown" would use wind again, "swaying" would sound too gentle, "undulating" would be convoluted, "dancing" would sound too cheerful...)
Feel like I'm taking the easy road here, defending one of the most popular poems of all time, but there it is.
Also, it both isn't melodramatic ("clawing" trees, for instance; this is a high-adventure poem, not Poe) and doesn't detract from the mood ("wind-blown" would use wind again, "swaying" would sound too gentle, "undulating" would be convoluted, "dancing" would sound too cheerful...)
Feel like I'm taking the easy road here, defending one of the most popular poems of all time, but there it is.