This is a mod which brings a little bit of Twilight Forest into your worlds, in the form of the Rainbow Oak tree.
Rainbow Oaks can rarely be found in Flower Forest biomes, and come in a variety of shapes, sizes and colours, adding variety and decoration to your world. You'll also find their saplings in village blacksmith chests and some dungeons and temples.
The biomes they appear in, how common they are and which chests the saplings are added to can all be managed via the mod's configuration file.
This mod uses textures from, and contains some code from, The Twilight Forest by Benimatic. Thank you to Benimatic for creating Twilight Forest, and for releasing it under an Open Source license.