Wood might be the oldest working material used by humankind. Even before people began to make stone tools, they would have used branches, clubs and twigs in order to make everyday life easier, be it for hunting or for making camp. And so we can assume that in the Viking Age, too, wood appeared as the most common working material for all sorts of every day objects, even though be historically speak of the "Iron Age" (for Northern Europe), which rather reflects the "material most difficult to produce for everyday use", however[citation needed].
Compared to bronze or iron, which has to be extracted from ore, wood literally grows "just around the corner". And so it is of little surprise that there are some wooden finds from the Viking Age as well - some of which being in an excellent condition.
Wood can be worked with the simplest tools. Many of those tools didn't change in their basic form during the millennia. It becomes obvious if one takes, for example, an ax, a carving knife, a chisel or a spoon bit: the basic form, sometimes even the details, can be found if not until today, then at least until the 19th or 20th century with a wide geographical distribution 1 .This fact benefits the interpretation and portrayal of Viking Age woodworking since except for a few prominent finds, there aren't many direct sources dealing with this craft around that time. One often has to use tool marks on worked pieces from the period, together with a geographical and temporal interpolation, in order to get a reasonable picture. The re-enactor might spot a great advantage here because an old, cheap draw knife and some old spoon bits from (online) flea markets might, together with fitting handles, act as a reasonable-authentic tool collection.
But tools are just the beginning of the craftsmanship. Materials, working techniques and -places still have to be reconstructed as good as possible. While authentically splitting an oak tree for getting planks might still be possible for some people, we still have to make compromises using modern solutions for finishing our nice wood carvings: Shark skin for smoothing is not likely to bee looked at sympathetically (of course horsetail plants for polishing are okay) and nobody wants to get in contact with lead oxides and other rather unhealthy Viking Age pigments when painting the finished product. But apart from that, there is still linseed oil and beeswax as environmental friendly timber proofing.
1 Arwidsson, Greta, "The Mästermyr find: A Viking Age Toolchest from Gotland"