The most obvious way that death is present as a theme is through the fact that Myop discoveres an actual dead person in the forest, and has to come to the harsh reality that people die, and sometimes in horrible and cruel ways. The details of the corpse--the teeth, eye-sockets, rotted clothes--all add to the strength of that theme.
Beyond that, however, death is present symbolically also. After her discovery of the noose, Myop's childhood, innocence and naivety die. Walker symbolizes the death of Myop's childhood by having Myop lay her flowers down on the ground, almost like she is not only at the gravesite of the dead man, but at the gravesite of her former happiness and childhood. She pus the flowers down almost like she is mourning at a spot of death--for her, this is the spot that she realized that she lived in a harsh, cruel world where her innocence could no longer thrive. This symbolic death of Myop's innocence is further symbolized by Walker's last line, "And the summer was over." The summer is typically associated with carefree happiness, life in full bloom; ending the summer symbolizes the death of Myop's full-bloomed happiness.
So, Myop's life takes a turn in this story; her former self dies, taking with it her innocence and happiness. I hope that helps a bit; good luck!