Both the Tree of Life and the Tree of the knowledge of good and evil are eternal. Like each of us, they are both natural and supernatural simultaneously.  The Tree of the knowledge of good and evil will stand forever as a testimony to the foolishness and rebellion of man  - against all who chose it's fruit over God's will for them. It will forever testify of theyvwho chose to discontinue fellowship with God   -  who prefer each other's company to His. They even prefer Satan's fellowship to God's,  and so they shall have it, forever. 

The Tree of Life will forever stand as a testimony to all those who chose fellowship with God over their own lives. They chose obedience over rebellion.  They chose to pursue Him over knowledge about Him. Everyone born of the flesh is born out of fellowship with God. Everyone born of the Spirit is born into fellowship with God.  Those born of the flesh alone prefer to fellowship with flesh alone. Those born of the Spirit prefer to fellowship with the Spirit  - having crucified the flesh with it's affections and lusts thereof. Those born of the will of the flesh  (the will of man), prefer to obey the will of the flesh (the will of man). Those born of the will of God prefer to obey the will of the Father.

The fruit of eating from the tree of the knowledge produces a religion men call "science"  - the pursuit of knowledge.  This replaces the pursuit of God; hence, science cannot admit God exists nor that He teaches truth, for in their pride, they themselves must discover,  or learn what is true, what is fact. They become their own gods, as Satan told them they would, but they are mortal gods, for the one realm they can never access or conquer is Eternity. Their powers are limited, they're unable to sustain the life of the flesh,  all must succumb to death. It is sadder than any Shakespearean tragedy ever was, for their desire to be gods, apart from God, will be granted.  They shall live forever as gods in hell and the lake of fire, eternally tormented by the prideful choices they made while in the flesh.