This is a Nether tree, as added by Natura.
The tree appears pale and ghostly as the name suggests; the wood is a dull grey and the leaves are almost white. Like others, the logs provide 4 wooden planks. The planks can be made into a Ghostwood Door and their own set of tools.
The Ghostwood tree is affected by the Treecapitator mod.
The tree is found in the Nether growing on the ground. It can be transplanted to the Overworld as long as you plant in on a Tainted Soil or Netherrack block. You can place the sapling on regular dirt, but it won't grow unless it's on the special blocks found in the Nether.
Like all trees, it can be forced to grow with Bone Meal.