28 . 12 . 12
POST UPDATE: As of 2015 we have been using a Spanish grown and produced plywood made from FSC certified poplar. It is lightweight and traceable, so perfect for what we need.
Plywood is clever stuff, at least we think so. If you take a piece of plywood and a piece of lumber (“normal” wood) of the same species and the same size as the plywood, then the plywood will tend to be both stronger and more flexible. Plywood is made by taking thin veneers of wood and sandwiching them together, with the grain direction of each layer lying perpendicular to that of the layers both above and below it. Because the finished plywood has grain running in two different directions, and across multiple layers (diluting the negative impacts of any material imperfections such as knots), it is much stronger and more resistant to warping, splitting and cracking. It’s a delicious wood sandwich.