This verse doesn’t contradict the fact that God forbade to eat from the knowledge of good and evil. First, the tree wasn’t created until God made the Garden of Eden where man was placed (Genesis 2:8). However, the fact is, the message in Genesis 1:29 isn’t all-inclusive, and its point is clear, and wasn’t meant to be taken technical as saying that absolutely any tree formed can be eaten, but in general.
1:29 Then God said, “I give you every seed-bearing plant on the face of the whole earth and every tree that has fruit with seed in it. They will be yours for food.
Problem: The word xylon denoted both a tree and a cross figuratively (being made out of wood). This is clearly the case here with Paul, who in Galatians 3:13 refers to the cross as a xylon, yet in other places obviously acknowledges a belief that Jesus was crucified on a cross (stauros) and not a physical tree (e.g. Galatians 5:11, 6:12, Philippians 2:8, 3:18, etc).