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BASIC PROPERTIES The outer-most layer of a tree trunk is the bark, which should be carefully saved and stored as it can often be used in dyes and medicines. The next layer in is the sapwood, which is lighter in color and more porous. This section carries moisture and nutrients for the tree. The darker heartwood is next, which is the part of the tree formerly sapwood, but no longer used to carry moisture and nutrients. The heartwood is more stable and rot-resistant than sapwood.
LIST OF CHARACTERISTICS *Aesthetics* Color: Woods range in color from white (holly) to black, including brilliant purples to rich browns. Because of the different nature of the sapwood and heartwood sections of wood, the same board can exhibit wide color variations. Texture: Some woods feel coarse, exhibiting large variations between the hard and soft grain areas. They may also have noticeably large open pores. Others exhibit little variation in grain areas and have small, closed pores. These types of boards appear and feel smooth, hard and uniform. Grain: Because wood cells line up parallel to the length of the tree, and because some areas are more dense than others, the cells orient in lines along the edges and faces of a board. Straight-growing trees tend to produce boards with straight grain lines. Boards cut from trees that curve or twist often have grain running at an angle across the board. Areas of the tree near branches or roots and certain defects produce grain with highly irregular patterns. Figure: Figure refers to the wood's surface appearance. Varying grain patterns can produce a wide variety of figures in wood, identified by names such as curly, fiddleback, and birds-eye, just for a few examples. *Working Qualities* Cutting: The more uniform and soft the wood is, the more easily the boards can be worked. Hardwoods with irregular grain are difficult to work by hand. Planing: The grain patterns of certain woods make them more difficult than others to smooth with a plane blade. The cells in irregular-grained woods and in areas around defects in normally straight-grained woods tend to shear off roughly rather than slice smoothly. Shaping and Turning: The density of the wood and grain directions determine how a wood reacts to being shaped or turned on a lathe. In general, heavy, dense woods with straight grain are easiest to turn smoothly and produce sharply defined and splinter-free profiles. Bending: Some woods bend much more easily than others. In general, hardwoods are less susceptible to breakage than softwoods. Fastening: The ability of wood to hold screws or nails is dependent on the type of wood. The denser and harder the wood, the better the wood will hold fasteners.
WOOD SEASONING Although it is possible to work with green wood, your chances of success will be much greater if you use cured or seasoned wood. Due to the fact that the heartwood dries at a different rate from the sapwood, stresses and strains take place as the green wood dries out. These stresses cause logs to split and the ends to check (crack from the center of the log to the bark). Seasoning is therefore advised. This is accomplished by first painting or waxing the cut ends and openings in the bark wherever side branches have been cut off. A good method is to take an old candle and coat the exposed wood with melted wax. Then mark the date you are starting the seasoning process. The wood should then be stored in a dry, airy place, away from sun and rain, with pieces of scrap wood positioned between the logs and timber to promote air circulation. Every few months turn the wood, inspecting the ends to see if checking (ie: cracking or splitting) has opened the sealant; if it has, apply more wax. After a Turn and a half your wood should have cured and will be ready for use. Some craftsmen claim that logs season better if they are stripped of their bark. If you are seasoning your logs in a personal storage area or in a dry cellar, this might be advantageous, because the bark usually houses many undesirable insects. Depending on the intended use for the wood being seasoned it might be more successful if the green log is first sawn into planks and beams, because logs are more susceptible to checking and splitting than planks and beams and also take longer to cure. Again, liberally coat the ends of each piece with a sealant. If you are carving and wish to work with green wood, the secret of carving it is to drill a hole completely through the piece from top to bottom. This allows for expansion and contraction of the wood as it dries out. Once drying has occurred, you can fit a wood plug into the bottom and the uppermost hole and carve or sand the plugs to conform with the design. Carvers have often carved masks and plaques out of green wood, hollowing out the reverse side to prevent cracks and splitting.
References "Working
Wood" - Jim Tolpin
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