These are amazing: each Joining a neighbor, as though speech Were a still performance.
Okay, we need to start with the title: "Some Trees." Imagine if we didn't have a title? What would we make of "these?"
Luckily, we can guess that "these" are presumably the trees the speaker's admiring. They're amazing for lots of different reasons, but it looks like the speaker is just trying to appreciate them for what they are and how they look together. But why not remind the reader that "these" is referring to trees? What's Ashbery trying to do (or not do) here and why? We'll have to keep reading to find out.
Notice too the rhymingcouplet of lines 1-2: "each" and "speech." In fact, the entire poem is written with various kinds of rhyming couplets. So we're beginning to notice a definite rhythm here that makes the whole thing sound fluid and orderly. (Check out "Form and Meter" for more on that kind of stuff.)
We also get some enjambment too that joins line 1 to line 2. So "each" tree may be special and "amazing," but it's also part of a community: "joining a neighbor." But how does a tree join a neighbor?
Well, maybe it has no choice. It is a tree after all and it doesn't get to decide who its neighbor will be. That's up to nature and the guy (or gal) down the block who decides to plant a tree.
Let's think of it this way too: from a distance a bunch of trees may look like one giant blob of foliage. So even though there are individual trees, they're still part of a big ecosystem. So they're "joined" together whether they like it or not.
What about the tone of "joining a neighbor?" There's something friendly about it, hospitable, maybe peaceful.
There's some personification here too, since trees don't usually regard one another as neighbors. In fact, they don't regard anything since, you know, they're trees.
So immediately we begin to suspect that Ashbery is using these trees as a metaphor of some sort. The speaker's not just digging nature and chilling in the park. These trees are meant to tell us something.
Just what that something is remains to be seen. Although, we're starting to notice a separation of one from many that seems to be getting at how an individual relates to the bigger world around it. First we get the word "these" and then we get a more individualized word, "each."
There's some figurative language too in lines 2-3: "as though speech / Were a still performance." Here we're starting to see a connection between those amazing trees joining their neighbors and the idea of human relationships and people "joining" one another. More specifically, these lines are an example of a simile, which makes that connection between trees and people even more apparent with the speaker's use of the word "as."
But what else can we make of lines 2-3?
We have more enjambment here, so we're meant to read them as one continuous thought.
As for the thought itself, let's consider a few ideas. First, speech is a human convention. We use it in lots of different ways but here it sounds as if "speech" is something artificial since it's related to a "performance." When we perform we're not being ourselves. We're being someone else either on purpose or otherwise. And if it's "still," there's something even more stilted, or unnatural, about it.
So if we begin to imagine relationships, we start to understand the metaphor here a bit more. Relationships often start out in unnatural ways: awkward moments, uncomfortable silences, things we don't mean to say, etc.
Also we end line 3 with a period, which means we should take a moment to really consider the completed thought. That "still performance" is important.