The Symbol of
Wood in Scripture symbolizes natural instinct that does not have the Holy Spirit. It is entirely of the earth, without knowledge of or faith in Jesus. It is a life that can be molded and crafted for a temporary good, but it is only temporary, just like wood.
Scripture says, "Cursed is anyone hanged on a tree." Deuteronomy 21:23 Perhaps because it is the symbol of a life lived without God, and therefore, it is a lost life and a lost soul. When Jesus was crucified on a wooden beam, it was the same notion as being crucified between two notorious criminals: he was identifying with, and dying in the place of, godless sinners. When we have faith in what he did on the cross for us, he gives us his Holy Spirit, and our lives that were previously led by our own natural instincts are now new creations, lived with the help of God's Spirit and Word within us.
People wonder why the Ark of the Covenant can't be found today, and I would say: it was wood overlaid with gold. Gold is the symbol of perfection, but wood is temporary natural instinct. Just so: the Old Covenant that the human-made Ark represented was God's perfect Law that was placed upon sinful people, like the gold placed upon wood. The Ark of Moses was never intended to remain, any more than the Old Testament Law was intended to remain. It all pointed to a heavenly Covenant, and a heavenly truth, and when Jesus took our place and died for us, the Temple veil was torn in two, and the Old Covenant was replaced by the New Covenant in Jesus's blood. The Old Covenant and the old Ark were spinkled by the blood of actual brute beasts, actual animals of the earth; but the New Convenent was sprinkled with the blood of God's only begotten Son.
God was angry at the Israelites for worshipping idols made of wood. He said, "Half of the wood you build a false god with and you set it up to worship it; while the other half you burn in the fire." Isaiah 44:19 He points out the brute beast nature of a mind that would do something so silly; and to worship wood, which by itself symbolizes natural instinct without God, so it was doubly foolish. They only exalted and bowed down to what was a symbol of their own foolish, sinful nature!
So, wood symbolizes natural and self-condemned earthly instinct without God's Holy Spirit.