As the poem opens, the speaker pays careful attention as something peculiar happens nearby. There's a "Murmur in the Trees," they observe—a gentle sound, "not loud enough" to be a wind, though you might almost mistake it for one.
The speaker is sensitive to the sound's strangeness, but they're not alarmed, not wondering What on earth could that be? They know that there's something odd about this sound, but they accept it patiently, calmly, almost matter-of-factly: they merely "note" it.
As it happens, the murmur is only one of the odd things in the landscape around them. They also note:
A star—not far enough to seek—
Nor near enough—to find—
This "star," in other words, tantalizes: it's not so far away that the speaker feels compelled to go hunting after it, but not so close that they feel they could reach it, either. It hovers at an ambiguous, unguessable distance. Maybe it's a real star; maybe it's just a glowing spark in the woods, a light carried by whatever is murmuring in there.
This vision of a winking star that looks both close and unreachable introduces this poem's emotional world. This will be an exploration of the mysterious, the inexplicable, and the magical. To this speaker, the world is full of presences that, while they never come "near enough—to find," are nonetheless real. Those who want to encounter such presences, these first lines suggest, will have to be open, sensitive, and patient, willing to accept sights that they'll never be able to explain or understand.
The speaker's parallelism in this first stanza prepares readers to understand how delicate such discernment might be. The murmur is "not loud enough—for Wind"; the star is "not far enough to seek." Perceiving magic in the world, then, demands an understanding of what isn't. The mysteries the speaker has described so far could be written off as the wind or an ordinary star. You'd have to know the wind and the stars very well to distinguish between them and the sounds and sights the speaker describes now.
Dickinson will use one of her favorite forms in this poem: the ballad stanza. That means that each of this poem's five quatrains is written in common meter, an alternating pattern of iambic tetrameter (lines of four iambs, metrical feet with a da-DUM rhythm) and iambic trimeter (lines of three iambs). Here's how that sounds in the first lines:
A Mur- | mur in | the Trees— | to note—
Not loud | enough— | for Wind—
This rhythm turns up often in folk songs and hymns. Here, appropriately enough, Dickinson will use a familiar form to describe magic hiding in plain sight.