As a child, Aaron got lost in the woods behind his school. However, he does not recall the event until several decades later. With the help of his therapist, he suddenly remembers how frightened he had been all alone in the woods. Aaron's blocking of this traumatic childhood event is an example of

Aaron's block from this traumatic childhood event is an example of dissociative amnesia.

Explanation:

Dissociative amnesia is the type of amnesia that causes the blocking of memories of traumatic and stressful events. it is usually associated with childhood memories, where the child suffered such a stressful time in his life that his brain created a blockage so that the information of that moment could not be recovered.

An example of this can be seen in the question above, where Aaron cannot remember the terrifying day he was lost in the forest.