Wood is a Steam-tier material. It can be extracted from almost every natural item, vanilla tool and, of course, any log. GregTech 5 nerfs the amount of planks obtained from one log of wood, unless Saw or Cutting Machine is used. However, Wood Pulp can be compressed into Wood Plank which substitutes planks in all recipes, and this is even more effective.
Wood can be burned into Charcoal, which is the best earlygame power source. It is also used in lots of recipes of all kind.
Due to the excessive bulk of including all GregTech 5 blocks and items this navigation box only holds ~10% of all. The reader can view This and This navigation boxes to access the rest.