Rubber Wood is the component of Rubber Trees.
Sometimes, Rubber Wood blocks have a Resin Hole. Right clicking the spot with a Treetap will produce 1-3 Sticky Resin, which can be smelted into 1 Rubber each in any furnace or extracted in an Extractor into 3 Rubber . Be aware that right clicking an empty (dark) Resin Hole may produce extra Resin, but is very likely to permanently remove the Resin Hole. Therefore, it is advised to be careful when extracting Sticky Resin.
The wood also has a small chance to drop the Resin when it is being chopped down, but this is not very productive without a supply of Rubber Tree Saplings.
Rubber wood can be placed in an Extractor to recover one rubber per block of wood. Rubber wood can also be placed in an Industrial Centrifuge in which case 16 wood blocks will produce 8 Carbon Cells, 4 Methane Cells, 8 sticky resin and 6 Plantballs.
Rubber wood, when processed in an Industrial Sawmill, produce 1 sticky resin per wood, making it the most efficient way to get rubber but no other side products are made.
Alternatively it can be burnt in any furnace to recover a block of Jungle Wood.