cmt

• Wood is that fibrous substance which composes the trunk and branches of a tree that lies between the pith and the bark.
• Outer bark provides mechanical protection to the softer inner bark and also helps to limit evaporative water loss.
• Inner bark is the tissue through which sugars (food) produced by photosynthesis are translocated from the leaves to the roots or growing portions of the tree
• Cambium is the layer between the bark and the wood that produces both these tissues each year.
• Sapwood is the active, “living” wood that conducts the water (or sap) from the roots to the leaves
• Heartwood is the wood extending from the pith to the sapwood.
• Pith is the small, soft core occurring near the center of a tree trunk.
• Medullary rays are sheets or ribbons of cells running from the inside of the plant to the outside.
• endogenous refers to tree that grows by the addition of new material inwards.
• exogenous refers to tree that grows by the addition of new wood outwards, immediately under the bark.
• hardwood refers to trees whose trunk divides to develop large branches, have branches that are larger and irregular, have broad leaves, are slow growing, valuable, harder and more durable
• softwood refers to trees which have straight trunk, smaller branches, needle-like leaves, symmetrical in shape, grow quickly, cheaper, softer and less durable
• Interlocked‑grained wood refers to wood in which the fibers put on for several years may slope in a right‑handed direction, and then for a number of years the slope reverses to a left‑handed direction, and later changes back to a right‑handed pitch, and so on.
• Diagonal‑grained wood refers to wood in which the annual rings are at an angle with the axis of a piece as a result of sawing at an angle with the bark of the tree or log.
• Spiral‑grained wood refers to wood in which the fibers take a spiral course about the trunk of a tree instead of the normal vertical course.
• Straight‑grained wood refers to wood in which the fibers run parallel to the axis of a piece.
• knot is that portion of a branch or limb that has been surrounded by subsequent growth of

  the stem.
• shake is a separation along the grain, the greater part of which occurs between the rings of annual growth.
• check is a separation of the wood that normally occur across or through the annual rings.
• split is a separation of the wood through the piece to the opposite surface or to an adjoining surface caused by tearing apart of the wood cells.
• bow is the distortion of lumber in which there is a deviation, in a direction perpendicular to the flat face, from a straight line from end‑to‑end of the piece.
• crook is the distortion of lumber in which there is a deviation, in a direction perpendicular to the edge, from a straight line from end-to‑end of the piece.
• cup is a distortion of a board in which there is a deviation flatwise from a straight line across the width of the board.
• twist is a distortion caused by the turning or winding of the edges of a board so that the four comers of any face are no longer in the same plane.