Identifying old wood (ii) a case study on chestnut

When we first moved into our house, it was suggested that the trim was chestnut. The American Chestnut is an incredibly versatile wood. Before the blight destroyed the majority of American Chestnut trees in the early 1900s, these trees could grow in excess of 100ft tall, with diameters of 5-7 feet. Accidentally introduced into the US in 1904 on Asiatic chestnut trees, the blight Cryphonectria parasitica ravaged the chestnut forests over the next 30 years, killing billions of trees. Before the 1940s, chestnut was widely used because it was abundant, and had good woodworking properties. In Toronto it must have been extensively used for trim purposes from 1900 to the late 1930s. My house was built in 1926, by which time this lumber had been drying for a number of years before being processed.

The problem with chestnut is that it looks quite similar to oak. So how does one tell them apart? By looking a little closer. Here is a sample of what is supposedly chestnut.

Both chestnut and oak are ring-porous – chestnut has bands of large earlywood pores (which appear more oval than round), and some tyloses (as does white oak). Chestnut can be easily distinguished from that of the oaks by looking for the rays. Rays are groups of cells that extend from the pith to the bark. All species of trees have rays but they vary in size. In chestnut, the rays are small and cannot be seen with the naked eye. In the oaks, the rays are very wide and thus are readily visible to the naked eye.

The presence of the rays, says the piece of wood is not chestnut, and the existence of the tyloses, implies that the wood is most likely white oak. Below is a table of common differences between wood characteristics of white oak, red oak, and chestnut.

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