Describe your suggestion

Consider adding twilightforest:root and twilightforest:liveroot_block to ars_nouveau:harvest/fellable. This would make it so that roots and liveroots are harvested when using Fell on Twilight Forest trees that have connected roots.
If you do this, maybe also put something in the questbook to ward off "my tree left an ugly hole in the ground" comments?

Why would you like this added/changed?

Convenience, also consistency with Mangrove Roots

Seems reasonable! I'll look into adding it for the next update.