As poem titles go, it doesn't get much clearer and straightforward than this one. Jarrell wants us to know right away exactly what is at the core of this poem. He sets us up for a poem about war and death, and he delivers it. But the title works on another level, too (yeah, you're right, that seems to happen a lot with this poetry stuff).
You probably noticed that the stark clarity of the title feels really different than the poem's more figurative first line. This sharp contrast between the stark reality of the title and the more figurative, almost surreal, quality of the first line gets the reader's mind ready for all the contrasting elements that we are confronted with in this very short poem: life and death, dreams and nightmares, nurturing and destroying.
The poem gets its power, its impact, from these contrasts. Life seems more precious, delicate, and fleeting in the face of death. It's like how putting Milk Duds in your popcorn makes the popcorn pop-ier and the Milk Duds, well, Dud-ier. The sense of life in the poem and the sense of death in the poem both gain power from their proximity.
In that way, then, the title sets us up to think in one straightfoward direction, knowing all the while that the poem will soon be zagging our minds another way