The tree is one of my favorite symbols.
When I was a child I memorized this verse.
1Blessed is the man that walketh not in the counsel of the ungodly, nor standeth in the way of sinners, nor sitteth in the seat of the scornful.
2But his delight is in the law of the LORD; and in his law doth he meditate day and night.
3And he shall be like a tree planted by the rivers of water, that bringeth forth his fruit in his season; his leaf also shall not wither; and whatsoever he doeth shall prosper.