God placed mankind in a fruitful, lush garden, out of which he was kicked (Gen 2-3).
At important points in the developing story we hear of a world-tree (Dan 4) and a vine with many branches (Ezekiel 17), and of a coming Branch who will sprout from David’s line and restore God’s people (Isa 11; Jer 23; 33; Zech 6).
Christ arrives on the scene and not only teaches that the kingdom of God is like a mustard seed that becomes a huge tree (Mark 4:30–32) but also declares himself to be the vine (John 15:1), in whom we bear fruit. And along the way of faith, we are beset with 'thorns' (2 Cor 12:7-10) that ultimately make us more, not less, fruit-bearing (John 15:2).
Could it be that the very reason there is such a thing as botany--the very reason there is such a thing as a tree--is so that God might give one more picture to his people of his great salvation?