GR translation: each long frond hanging, stung, dizzying

[Mike Jing]

P228.8-13   Waves crash and drag at the stones of the beach. The
harbor has broken out in whitecaps, so brilliant they can’t be
gathering their light from this drab sky. Here it is again, that
identical-looking Other World—is he gonna have this to worry about,
now? What th’—lookít these trees—each long frond hanging, stung,
dizzying, in laborious drypoint against the sky, each so perfectly
placed. . . .

Is the frond "stung"?  If so, by what?  Or am I reading it completely wrong?