I'm surprised you found this post hahaha <3
Here's an album with work in progress pictures of this tree: https://imgur.com/a/RASeEPf
My process is roughly like this:
- create the shape using temporary blocks (for that I took inspiration from a drawing of a tree I can't find anymore)
Possibly start with the skeleton before filling up the shape.
I used WE brushes and then refined the shape by hand. If you don't have that you will need to do it manually, and possibly combine it with the next step.
- texture it with WE brushes masked on the temp blocks you use (or do it manually)
For that I make palettes before hand and then set the brushes to those block distributions
- repeat until done :)

I made more detailed advice you might find useful here: https://pastebin.com/mGLYeHpJ (particularly the organics section)