The humble beginnings. 40% chance to survive if planted by a player.
First growth stage. That one leaf block can potentially already bear fruit.
A growth stage can either be the tree getting taller...
...or filling out the leaf block spaces...
...in several steps.
Once it has reached the max height of 6 blocks...
...the lower leaf blocks will vanish...
...and it will instead grow in width to a maximum of 2 away from the stem.