Trying all the seeds out in creative to see their generation since I just got BoP and this compat mod. The Hellish Acorn is the seed of the Hellbark Tree from the Nether. However, after a couple of growth cycles (usually 2 or 3 bone meals) it stops growing and turns the netherrack underneath into the rooty dirt the other trees create in the overworld. (I'm going to assume this stops the plant's growth) This sapling sized tree usually grants only 1 log of hellbark!

I did the following tests before posting this:

1. Confirmed latest installs of BoP, DT & DT BoP compat mods.

2. New Gen with ONLY Biomes o' Plenty enabled. Sapling can be placed and grown on dirt (or dirt with grass) and overgrown netherrack. Provides 2 logs and about 5 leaves. Block underneath remains dirt or is converted to netherrack (if it was the overgrown netherrack)

3. New Gen with Biomes o' Plenty, Dynamic Trees and Dynamic Trees BoP compat mod enabled. Sapling can be placed and grown as before. Provides 1 log and 1 - 2 sticks. Block underneath is converted to rooty dirt regardless of what it was before. Block becomes dirt (obviously to be expected since it's rooty dirt at this point).

Based on BoP's version of the tree, I'm pretty sure it's meant to be a small bush-sized tree. However, I'll be turning all my overgrown netherrack to dirt at this rate!