The title gives an order the poem never repeats. There is no sign in the text, only meltwater lying on ice, which is reason enough to keep out: it is the thin, unreliable season between freeze and thaw. By the last line, though, the poem has gone somewhere a prohibition can't reach. A walker, watching small things in the woods, finds a patch of moss and remembers having slept there. The central idea is that close attention to a place can turn into a kind of memory. Warnings, markers and trails guide the body through a landscape, but what makes it personal is the time we have already spent in it.
The construction is spare. The poem has eight short lines in three stanzas of two, three and three, with no punctuation, no capitals and no rhyme. That compression recalls haiku, and the poem works the way many haiku do, by setting images side by side and leaving the reader to connect them. Most lines run five to seven syllables. The longest, "the click beetle's antennae," sits in the middle of the poem, as if stretched out by the very feelers it describes. Instead of rhyme there is a quieter echo of vowels. The long *i* in "ice" returns in "find" and "night," so the first and last stanzas are tied together even though one describes a surface and the other a memory.
The opening image is all surface. "Meltwater shimmers / atop the ice" keeps the eye on the top layer, with nothing below it. Shimmering suggests light and instability, a skin of water that is neither solid nor properly liquid. This is the season the title seems to warn about, and the poem never goes in.
The middle stanza changes the scale and brings in the human world. "Plastic trail marker" is a blunt phrase, without a single soft sound in it, and it names something put there to tell people where to go. Then comes a small ambiguity in the line breaks. "The click beetle's antennae" could belong to the marker line, as if the beetle were perched on it, or it could simply be the subject of "sweep back and forth." The reader hesitates for a moment, which suits the image. The antennae feel their way along, and the beetle seems to be searching for a route, much as a hiker follows a blaze. Its name also carries a sound, the small snap of an insect flipping itself over, so a little noise slips into a very quiet poem. "Sweep back and forth" imitates its own motion, and that backward-and-forward movement anticipates the turn the poem is about to make in time.
In the last stanza the setting becomes "ancient hemlock grove," and the first-person pronoun appears only now, in the seventh line. Until then the speaker has been a pure observer. "Ancient" sets a huge span of time against the single word "once" three lines later, and the human scale is tiny beside the trees. The verb "find" suggests the speaker was not certain the spot could be found, or perhaps was looking for it without saying so. The moss is the right object for the memory. It grows slowly, it is soft, and it can hold the shape of a body for a while. It is also the opposite of the plastic marker, a trace left by a person that is gentle and almost invisible.
The poem is also careful about what it withholds. It never says why the speaker spent the night there, or how it felt, or whether coming back brings comfort or loss. The final line, "where I once spent the night," ends with no full stop, as if the memory just carries on. The title then reads differently. Swimming is forbidden, but sleeping outdoors in an old forest is a deeper way of entering a place, and the poem quietly sets the two against each other.
What makes the poem worth reading is how much it does with so little. It has no argument and no grand statement, only a thaw, a beetle and a patch of moss, arranged so that the present quietly gives way to the past. It teaches the reader to look at small details, because the memory the poem finally reaches is found through them.