I supposed a good way to start off a glossary of turning terms is with the term "turning. " "Turning" is a catch-all phrase for all the different types of things that can be made on a lathe. A turning is essentially any hunk of wood that has been mounted to a lathe and shaped as it spins around. Most of the time, for me, the turning is some type of bowl, vase, goblet, or hollow form, but I also make other turnings occasionally, like pens, toys, and tool handles.
In the photo at the right the plum wood is spinning at about one thousand revolutions per minute as I hollow out the bowl section of a plank-rim bowl.
As beautiful as some woods are, natures beauty is not limited to the beauty of the wood itself. There are other natural elements at work that can drastically change the way a species of wood looks, sometimes even making an ordinary, unspectacular species look exotic. The most common and most notable actors are the multitudinous types of fungus that can take up residence in a piece of wood. Some fungi will make the wood look terrible, but a great many types of fungi can exaggerate the existing figure, cause spectacular color variegations and even add additional elements to the wood.
The White Birch in the photo above has been affected in several ways by spalting. There are the brown streaks that are exaggerating the grain, the black streaks caused by the fungus attempting to setup barriers to other fungi, and, if you look closely, there is some bleaching of the rays that look like little white flecks. This piece of wood looks nothing like normal White Birch, shown in the photo on the left. In fact, had I not harvested the tree myself, it would have been difficult to identify the species.
Unfortunately, saying that a turning has "fungus" does not sound very appealing. Fortunately, there is another, much better, even intriguing word for it: Spalting.
Sapwood is the wood in a log that is located in the outer region of a log, closer to the bark. It is the living wood, as opposed to the heartwood which is essentially dead. In some species of wood, it can be difficult to distinguish the sapwood from the heartwood, but on most species, the sapwood is significantly lighter. With some exceptions, sapwood is generally undesirable for furniture making, but is entirely useful with turned items.
Heartwood is the wood in a log that is located closer to the center of the log. Heartwood, unlike sapwood, is essentially dead. Generally darker than the sapwood, the primary function of heartwood is to provide structure to the tree. The majority of furniture is made from heartwood.
The percentage of heartwood, as opposed to sapwood, varies from species to species. Species with a lot of heartwood are more likely, as such, to be used in furniture making, but both the heartwood and sapwood is useful in turing, and can even be used for contrast.
A natural edge bowl is a bowl that has bark remaining on all or part of the rim for an aesthetic effect. The typical way a natural edge bowl is made is by reversing the orientation of a bowl in the log from a conventional bowl (right). By orienting the rim of the bowl towards the outside of a log, the bark can be retained on the rim of the bowl. There are, however, there are may other ways of retaining some bark on the bowl (below).
A crotch is section of a tree trunk or branch that splits into two or more branches, forming a 'Y' shape.
The wood between the junction of the two branches is almost always highly figured. The type of figure in a crotch is distinct from other types of figure. Some refer to the figure in a crotch as feather figure because it resembles a feather.
The term figured is a general term to describe grain that is somehow different from the grain normally found in wood. There are many specific kinds of figure, like 'curly', 'quilted', 'bird's eye', 'burl', and 'crotch', but if the unusual grain pattern does not fall into one of these categories, it is usually simply called 'figured'