O if we but knew what we do When we delve or hew— Hack and rack the growing green! Since country is so tender To touch, her being só slender, That, like this sleek and seeing ball But a prick will make no eye at all, Where we, even where we mean To mend her we end her,
Just scanning over this second stanza, it looks like it would help to know what both "delve" and "hew" mean. To the dictionary machine, everybody.
To "delve," in this case, means to dig something up. And "to hew" means to chop something, usually with an axe.
So, the speaker is lamenting the fact that we (human beings) don't know what we're doing when we dig up, chop down, hack apart, or "rack" (fill with pain) the natural world. Nature is described here, using metonymy, as "the growing green."
The speaker continues, describing "country" (as in the countryside or Nature, not the country of England) as "tender" to the touch—both fragile and sensitive. The very being of Nature, its inner essence, is "slender" in the speaker's view, like a thin, almost frail woman. The speaker uses more personification to reinforce this idea, referring to the natural world as "her" (13).
Nature is so sensitive, in fact, that the speaker busts out a simile and compares it (or "her") to an eyeball (or "seeing ball" as it's put here).
How's that work, you ask? Well, if you were to get injured—"a prick" (15)—in your eye, you couldn't really see out of it all that easily, right? (If you've ever owned a BB gun as a kid, you know that this is why your folks were so worried that you'd shoot your eye out.) In fact, even an accidental poke is enough to reduce your eye from a magnificent organ of vision to just a ball of pain and tears. It really ceases to function as an eye at all.
This is the point that the speaker is making when he says that some injury "will make no eye at all" (15).
With this comparison, the speaker describes Nature as so fragile that any harm done to it will make it cease to be…well, natural.
In fact, the speaker goes on, even where we look to improve and repair our natural surroundings ("even when we mean/ To mend her"), we are fundamentally changing Nature (16-17).
Think about it: any interference by humanity—whether to repair or tear down—represents a kind of irreversible change. Nature that has been affected by humankind is no longer Nature. It has become a part, however small, of human civilization.
This is what the speaker means when he says that "we end her"—we stop Nature from being natural anymore (17).
When we hew or delve: After-comers cannot guess the beauty been. Ten or twelve, only ten or twelve Strokes of havoc únselve The sweet especial scene, Rural scene, a rural scene, Sweet especial rural scene.
Our speaker continues to make his case in these final lines. He notes that, once we cut down or dig up Nature (like the aspen trees), the folks who come after have no idea how beautiful the scene was before.
It might only take ten or twelve "strokes of havoc"—a figurative way to describe the blows of an axe—to "unselve" the natural beauty.
With the word "unselve," the speaker suggests that cutting down these trees is not just changing the beauty of the scene. It goes way deeper than that, changing the very essence of the natural word itself. In fact, those tree-choppers are undoing Nature's "self"—bummer.
"Yes," the speaker concludes, "it is a bummer." He reminds us that the trees made for a sweet, special ("especial") scene out in the country ("rural").
The repetition of lines 22 through 24 really drive home just how awesome those trees were, and how terrible it is now that they're gone.
The natural world just isn't the same without them—sniff.