I’m contemplating doing some carving on bog oak. Have you heard of it? “Bog Oak” is a bit of a misnomer; it is likely to be oak, but could be another species such as pine or yew. What is for sure is that it’s old, as in hundreds to several thousands of years old.
How can wood be that old? Whether it’s a punky log in the woods or a plank that can no longer bear your weight, wood rots. Fungi break down the structure of the wood cells to utilize the stored nutrients within. Insects speed the process by boring through dead wood on a macro scale. But these processes require two things: moisture and oxygen. Take away one of these and the wood resists decay. Wooden structures in arid or semi-arid locations can remain for hundreds of years, while those in temperate conditions collapse and crumble in a generation or so.
How can wood survive in very wet conditions? Through a combination of factors. The tannins in oak inhibit decay to begin with; the waterlogged wood, covered over time with earth, receives very little exposure to oxygen. The boggy soil is generally acidic as well. These factors all work together to inhibit fungal action (Incidentally, these same conditions are responsible for the preservation of “bog bodies”).
With time, the tannins in the wood react with iron salts and other minerals dissolved in the acidic soil and water, darkening and hardening the wood. The high mineral content makes bog oak difficult to carve; it dulls tools like no other wood I’ve worked. The mineralization also makes the wood more resistant to burning, making bog oak an attractive material for tobacco pipes. Bog oak is known as morta in the pipe industry.
Excavating the wood is a tricky process; most times, the wood already began to decay before being submerged or buried. The salvageable bog wood must be stabilized and dried carefully before being milled. As a result, bog oak is a very expensive lumber, and is most often used for small decorative objects such as pens, knife handles, or pendants (it was in demand during Victorian times for black mourning jewelry).
Bog oak is most commonly found in Great Britain, Northern and Eastern Europe, and Russia. My source for bog oak is in Ukraine. I won’t be ordering more wood from them for a while, because I expect they have other things to occupy them at the moment.