In reply to anonymousgames15:
No idea what it is I submitted a it as a bug on the development page but wasn't able to find out the cause. Luckly when hosting the mod on a server you don't see it but on singleplayer you could.
I'm making a personal mod pack and I keep getting this weird airblock that is black/pink it seems to appear on trees.
attached screenshot of the problem and my mod list.