All lumber undergoes color change after it’s milled. A freshly milled board will demonstrate the most significant observable color change in the first few hours or days after it’s cut or planed, but it will also continue to change color over time, and some species of wood will demonstrate this more significantly than others. While decking lumber faces constant exposure to the elements, when it comes to color change, some specific lumber species have particular chemical reasons for unusual amounts of color change. Cherry is one of those species.
What happens with Cherry is that regardless of whether a stain or other finishing products are applied, the color of the wood will change over time. Unlike water, which will allow the wood color to appear darker for a short period of time, stain or other finishing products applied to the wood will continue to react with the wood long after that finish has cured. Freshly milled Cherry appears closer to a light pink than the deep, rich, reddish brown color most of us associate with the term “Cherry finish.” Left on its own, Cherry will darken over time but to more of a basic brown than that classic “Cherry” color.
The only way to achieve that rich hue is a combination of dye or stain plus years of accumulated dirt and chemical change, all working together to deepen the hue. In order to attempt to achieve the look of antique Cherry furniture, which may have an appearance representing hundreds of years of the color change process, today’s furniture makers often go heavy on stain to achieve an immediate similar effect. While sometimes they don’t even use Cherry wood at all, when they do, that color will continue to change under the finish, making the resulting color, after years of exposure to air and dirt, quite different than your original desire.
If you want to see an illustration of interior color change in-person, simply pull back the corner of an area rug placed over a hardwood floor, and you’ll see a difference, as long as that rug has been in place for any length of time. Soil chemistry combines with species to create a unique combination of influences on the color change, but two of the components that make the greatest difference are extractives and lignins. Extractives are compounds that are sometimes extracted from the wood to create other products, such as pharmaceuticals. Lignins are water-resistant compounds that bind wood fibers together.
Both extractives and lignins begin to cause color change even before a tree is harvested. Extractives and lignins cause the change in color between sapwood and heartwood. They continue to cause color change when they interact with the longer wavelengths of light to which interior applications are exposed. In response to contact with heat and any chemicals applied to the surface, these components break down.
