A horse head in a tree is an image that refuses to behave. Horses belong on the ground, and trees belong to birds. Dave Bonta's poem doesn't say whether the head is a skull, a carving, or something grimmer, and that silence is part of the effect. The head is also just "head," not a whole animal, so it seems to have been separated from its body. What it "showed" the speaker is "the whole mystery of abuse." That is a startling phrase, because "mystery" promises something that can't be solved, while "whole" promises complete understanding. The poem claims both at once: abuse is entirely clear and entirely baffling.
The title, "Horse sense," is an idiom for plain, practical wisdom, and here it carries a dark joke. The insight comes from a stray animal head rather than from a wise person. Judging by the tone, the poem suggests that what the speaker learns is blunt, even animal knowledge, the kind we already have and prefer not to look at.
The second stanza moves from image to statement, and the pronoun shifts from "me" to "we." "We understand backward" echoes the familiar idea that life makes sense only in hindsight. In this context it stings, since we seem to grasp cruelty only after it has happened. Then the grammar loosens. With no punctuation to guide us, "dying more of envy than true love / kill other persons" can be read in more than one way. It may say that envy, more than love, is what we die of. It may also say that people in this state go on to kill others. The poem overturns a romantic cliché, because songs say people die of love, and here envy is the stronger killer. The verb "kill" also arrives without a clear subject, as if violence simply happens, which suits a poem about how abuse so often goes unnamed.
The last line, "but let the rules be," turns on its "but." It can be heard as bitter irony: kill if you must, just don't disturb the system. The word "persons," which is more formal and legalistic than "people," sits right beside "rules." The cold vocabulary matches the cold behaviour it describes, a world that tolerates harm as long as its arrangements stay intact. "Let be" can also mean "leave alone," so the line may be accusing us of a passive refusal to interfere.
The form is spare. There is no rhyme scheme, no capital letters and no punctuation, so the poem reads as free verse. Still, the lines have a shape. By syllable count they run roughly six, ten, six, nine, five, five, so the long, explanatory second line is followed by lines that shrink toward the end, like a door slowly closing. There is also a faint rhyme between the first and last line-endings, "tree" and "be," which frames the poem. The tree holds the image, and "be" is the shrug that ends it. A long "oo" sound runs quietly through "abuse," "true" and "rules," linking the harm, the love that is supposed to oppose it, and the structures that let it continue.
The poem is worth reading because it enacts its own claim. We get the image first and the explanation afterward, so as readers we also "understand backward," and even then not completely. In seven lines it holds a surreal picture, a thought about hindsight, an accusation about envy, and a sneer at obedience to rules. It never describes an act of abuse. The horse head stands in for the scene, and because the poem declines to explain it, the image stays lodged in the mind, like the head in its tree.