The various resources within this type are interchangeable for crafting common items. For crafting higher-quality blueprints, you will need to include two or more of these named resources, but not the generic resource.
Since the generic resources are all you can harvest at freeports and is all you will receive when you demolish structures, you will need to explore the game world in order to find many versions of resources of each type to build high-quality items and structures once you have looted some good blueprints.
The best way to gather wood is to collect it with a Elephant or a Metal Hatchet. You can also collect it with a Crude Tool or Stone Hatchet or various other tools or by punching a tree or in some places by harvesting whispy-looking bushes by hand.