Ethereal Saplings, Ethereal wood, and Ethereal leaves, planks, steps, slabs, fences, gates, and doors are present in Biomes O' Plenty 6.01 for minecraft 1.11+. They might be spawn in the unused biome Spectral Garden, which meant to generate in The End. Attempting to grow an Ethereal Sapling in normal biomes currently results in a standard oak tree.