The creation story reports that there were two trees in the garden: Tree of Life and Tree of Knowledge of Good and Evil. These are not to be interpreted as literal trees. Each tree has very clear symbolic meanings.

Trees are known by the fruit they produce. Good trees produce good fruit and bad trees produce bad fruit. In the bible, trees symbolically represent people. ***

See this link for understanding of the symbolism of the Tree of Life. And see this link for understanding of the Tree of Knowledge of Good and Evil.