Spotlight: Sapwood and Heartwood in Marquetry
In this post about artists in the Free Verse show at the Messler Gallery at the Center for Furniture Craftsmanship. I’m just going to talk about one piece, because some explanation might be helpful for people who don’t have woodworking experience.
Mature trees will generally have two different kinds of wood: sapwood and heartwood.
Sapwood is the wood closest to the bark. It is the most recently-formed wood in the tree, and it serves as the transport system that takes water and minerals throughout the plant. All wood starts out as sapwood, but as the tree grows and new layers of cells are added, the oldest sections of the sapwood transition into heartwood.
Heartwood is dead and can no longer be used by the tree to transport sap. However, even though the cells are dead, they are resistant to decay because of various chemical compounds, such as resins, terpenes, and phenols, that accumulate in the heartwood. Without these chemicals, the dead heartwood would rot quickly, and the tree would collapse as its inner structure deteriorated.
Both sapwood and heartwood can be used in woodworking. Sapwood, however, presents some challenges because it has a higher moisture content and lacks the chemical compounds that prevent heartwood from decaying. This is less of an issue in marquetry projects, as wood cut into a veneer can be dried pretty easily even if it starts out very wet, and decay is less of a concern in pieces that will be kept indoors, which most marquetry projects are.
There are aesthetic differences between sapwood and heartwood too. Typically – although not always – sapwood is lighter and heartwood is darker in color. Woodworkers usually gravitate toward the darker colors found in heartwood, but there are many reasons why sapwood might be a good choice for a woodworking project. But in most cases, woodworkers will choose either heartwood or sapwood, and not a piece of wood that contains both.
That’s not the case for Rochester-based artist, sculptor, furniture maker, and teacher Scott Grove, however. Scott has a really neat way to use the transition line between sapwood and heartwood in marquetry, as he did with his piece Messier 51, a box decorated with amboyna burl veneer.
Photos thanks to Michael Boyle
When I first saw the box from a distance, I assumed that the edges of the spiral were the seams between the pieces of veneer, like this:
But looking more closely, I realized that the edges of the spiral are actually the border between the sapwood and the heartwood, and the marquetry is made with many more pieces of veneer than are immediately apparent. It’s hard to see the joints between the pieces of veneer, especially because the burl works so well to mask the lines. So I’m 100% sure that I don’t have the lines drawn correctly, but the picture below is an approximation of the way the spiral is actually constructed:
