While these shots are in creative, I've already built the island, trunk and branches in survival on the ROG SMP. Lots and lots of grinding. Like, a week's worth, at least, and around 15 hours of build time, all done solo. Still need to place all of the leaves, but I've already gathered all the mats!
Why did I design this massive tree and island, you ask? Why, to hide my industrial area which currently includes: guardian farm, super smelter, cactus farm, and guardian farm's afk spot (which is also a tree farm), of course! That's the sane thing to do, right?!
Island: cyan terracotta, stone, moss, grass, tuff, mycelium, cobblestone, dirt, sea lanterns, moss carpet, and glow lichen
Bark: acacia wood, basalt, sea lanterns, gray carpet, and glow lichen
Leaves: green stained glass & panes, lime stained glass & panes, yellow stained glass & panes, azalea leaves, oak leaves, moss and soooooo many sea lanterns.
Shaders: ComplimentaryReimagined
Below is where it's at in survival. So hard to get ALL of it in a screenshot and looks a bit odd due to the lower view and FOV. It's 100% spawn proof to keep the guardian farm rates from falling.
Almost 300,000 blocks total when done (not including the farms themselves), and goes from sea level to build height.