When I convert a tree to Nanite, the leaves LOD to nothing (the leaves disappear). Can I set the Nanite LOD to a level that keeps the leaves at a low level without disappearing?
Nanite isn’t suitable for foliage, I have read many times… 
Nanite doesn’t support transparency. You could create a duplicate of the tree and set the alpha textures to something opaque (like a solid green?). Won’t look pretty but will work great for blockout ect.
Ya, I can use Nanite for the trunk and hopefully use foliage for the tree tops?