The Attic French Bar Cabinet (Walnut) A classy product made of premium solid wood. Solid wood is a living, breathing material. It ages over time like any natural material. Natural solid wood has characteristics which include knots, variations in grain, and colour differences. Seasoning and drying the wood reduces splitting and warping, but some natural movement is to be expected. Changes in climate and weather cause solid wood furniture to move. Knots are imperfections that happen during the growth of the tree. Grain differences are caused by the way the tree is cut. Each board will have a different grain direction. Natural colour variations are created during the tree growth. The colour of the wood is determined by where the piece was positioned within the tree. Lighter pieces are the ones closer to the bark while the darker pieces are the ones closer to the centre of the tree.