Standing Planter plus
The standing planter was a great carbon source. Many folks missed him very well.
(as far as I know he is missed only by the pc users. On the other platforms he is still available).
If u want u can reactivate him (it's a little bit cheating).
it's difficult to explain - Here is a description in form of a Video:
After reactivation u can install the mod. With this, the carbon grows every 20 seconds
(big thanks to goatfungus for create the nms save Editor)
Unzip and drag'n drop the .pak-File into your Mods-Folder (GAMEDATA/PCBANKS/Mods)
Modified is PLANTERWALLSHELVES.ENTITY
Ready for 1.71