How we cite our quotes: (Line)
Quote #4
But there are no trees, no natural shelter. (11)
Just to reiterate: there are no trees on the island (or any other natural shelter). Heaney goes out of his way to explain what Mother Nature has neglected to provide. He puts the image of trees and natural shelter in our minds (by writing it), and then quickly erases them by reminding us that they're not there. So, rather than being blissfully ignorant about what the people might want or need, we're painfully aware of what's lacking.
Quote #5
You might think that the sea is company,
Exploding comfortably down on the cliffs
But no: when it begins, the flung spray hits (12–14)
Again, the people look for company in nature, but it's a total no-go. The ocean spray, which at first seems soft and inviting, ends up being vicious during the storm. Heaney's totally calling us out here. He's all like, "Hey, you might think Mother Nature is cool and everything, but you'd be way off; she's being a real beast right now." This is similar to what he did in the previous lines with "no trees, no natural shelter." It emphasizes what comforts the island is lacking by bringing it up.
Quote #6
Turned savage. We just sit tight while wind dives
And strafes invisibly. Space is a salvo, (16-17)
Look out, now the wind has become totally vicious. Mother Nature has turned mean, and she's attacking the homes of the people. This seems to be the turning point in the poem where nature isn't just stingy, but downright violent and threatening.