What makes the patterns in wood?
The patterns in the board of wood can lead your eyes on a journey into wonderland. The light and dark streaks may remind you of busy highways roaming like ribbons across the land. The design may flow in graceful loops which resemble the waves of a gentle tide creeping up on a sandy beach. T Where is the Upper Volta desert?
These days, the mysterious continent of Africa is very much in the news. We learn of provinces in the Congo, for example, and towns in Ghana that we never knew existed. A map of Africa shows that the little country of Ghana, just north of the equator, is drained by the river Volta and this is the river which lends its name to the Upper Volta Desert.
The desert, however, is north of Ghana. It is, in fact, part of the southern region of the great Sahara Desert which stretches across northern Africa. The Upper Volta Desert is part of the arid territory of French West Africa.
he pattern may swoop in feathery whorls around a dark center like the eye of a bird. The wood of each tree presents us with its own beautiful pattern.
The pattern on a board of wood is drawn with light and darker lines running roughly up and down# tie call these lines the grain of the wood and an expert woodworker can tell the name of a tree from the grain. In a board of oak, the grain is coarse and the streaks are wide and far apart. In walnut the grain is fine, with the thin pathways close together. In certain pine woods, the coarse grain loops around hard little knots.
If a slab of wood is cut from straight across the trunk, we see these grain lines as round tree rings, one inside another. Each ring of light and dark wood is the layers of cells made during the changing seasons of a year. The new cells are added just under the bark of the tree.
In spring and summer when food is plentiful, the woody cell boxes are made large. In the fall, as the true begins to close down its workshop for the winter, the cells are made smaller and usually darker because more cement is added to their woody walls. These tree rings are added around trunk and branches like round cylinders from the bottom of the tree to the top.
A board of wood is cut from up and down the tree and the grain we see is an up and down slice of the rings which run around the tree trunk. The oak is a fast grower, adding a wide band of cells every summer which is why its grain is coarse. The walnut grows slower, adding fine grain to its wood. The pine tree drops its baby branches, sealing the wounds with hard cement. It adds new rings around these scars and when we slice the wood we see them as hard knots.
The tree rings are not perfect circles and where the branches join the trunk they curve around in various designs. These imperfect rings give us the graceful designs we call the figure of the wood. Aboard may be cut from the crotch of a sturdy branch or slant wise through the trunk. The figure on such a board may remind you of the waves and ripples around a tide washed island.
Some trees add their woody cells in irregular bulges. This happens in certain myrtles and in the knubby lump of wood called the redwood burl. These woods, when cut, show the most fantastic of all designs. The grain is twisted in curlicues of lighter and darker tints and some of this beautiful burled wood can be polished to look like mottled marble.