Spruce trees replace blocks made of blackstone in Modified Jungle Edge biome. No idea why it does this, and after testing it only works on about 50% of seeds. This is really strange, it only happens with spruce trees and only works with blackstone related blocks (blackstone bricks, stairs, slabs, blackstone, cracked, etc). Does not replace gilded blackstone. Only works when growing a spruce tree with bonemeal not natural growth