How Wood Gets Its Grain August 07 2013, 0 Comments
When a tree develops, it grows in concentric layers about the roots, trunk and limbs. If you were to slice through a tree member you would see these layers or “growth rings”. Each tree has a unique wood grain pattern, which is the product of its cycle of growth. Specific species are sought after because of their unique grain patterns. These grain patterns are what help give wood furnishings the warmth and beauty that only nature can produce.
The center of the tree is known as the pith. The next layer, or ring, is the heartwood which functions as a support. The cells that make up the heartwood are no longer living. The next ring layer is called the sapwood. It is through the sapwood that water, minerals and food are carried from root to leaf. The sapwood is generally lighter in color than the heartwood.
Between the sapwood and the bark rings lies the cambium ring layer. This is where the living of a tree takes place. The cambium is made up of ray cells and longitudinal cells which align with the tree trunk, and create the grain. The cambium grows rapidly in the spring and therefore is called springwood. Summerwood occurs later as the climate begins to warm. The summerwood is often darker and denser than the springwood. The cambium will then go dormant in the cold winter months. And the process continues for the life of the tree.
Types of Grain
Interestingly, the way in which a tree grows has a direct effect on the grain pattern. Also, the grain of the tree will display differently depending on the direction the tree is sawed, ultimately revealing unique patterns in the wood grain.
End Grain – produced when the board is cut perpendicular to the grain or “across the grain”.
Plain Grain – produced when wood is sawed parallel to the grain and tangent to the growth rings.
Quarter Grain – produced when wood is sawed through the radius of the growth rings but parallel to the grain.
The grain’s appearance is also affected by the size and configuration of the cells of the wood species. Hardwoods differ from softwoods because they have special longitudinal cells, called vessel cells. When the vessel cells are sliced open they reveal tiny holes called pores. (Conversely, softwoods do not have pores.) This adds another element to the grain’s appearance.
You are probably beginning to see why wood is such an amazing material to work with. Not only is it structurally sound, but it is beautiful as well. I personally like to use reclaimed woods in my custom wood furniture and décor designs because it adds another level of beauty to the design - history. I also think it is a great way to sustain our future. Although many wood species are now being harvested in environmentally friendly ways, this was not always the case. We are paying for past irresponsible wood harvesting. Yet, by reclaiming that which has already been harvested, we have an opportunity to begin to right some of our past wrongs.