Darkwood Trees are only found in Dark Forest and Dark Forest Center biomes, but are very common and create a solid canopy above those biomes. They are shorter trees by Twilight Forest standards, being about 15 blocks tall. The trees have a trunk that branches near the ground, and form 3-4 oval-shaped sets of leaves. Darkwood Trees have Roots below them, both when naturally generating and when grown from a Darkwood Sapling.
Unlike other leaves, Darkwood Leaves do not let light through them, and also don't naturally decay when the Darkwood nearby is removed. Darkwood Saplings drop from Darkwood Leaves when destroyed, and can be found in Leaf Dungeon chests.
Darkwood can be made into Darkwood Planks, which can then be crafted into Darkwood Stairs, Slabs, Buttons, Trapdoors, Fences, Fence Gates, and Pressure Plates. Darkwood Planks, Slabs, Stairs, and Fences can all be found in Skeleton Druid Houses. All Darkwood items are required for the Maniacal Dendrologist advancement.