FPU L2Properties and gross features common to all wood

• Definition and parts of wood

  1. Wood is defined as the xylem tissue that forms the bulk of the stem of a woody plant

  2. Hard, fibrous material formed by the accumulation of secondary xylem produced by the vascular cambium
• Properties common to all Wood

  • Organic
  • Hygroscopic
  • Anisotropic
  • Susceptible to fungi and other decaying agents
  • Combustible
  • Good insulator when dry
  • Easy to work with any tools
  • Versatile
  • Renewable
• Vascular System


  • System of channels for the conveyance/transport of fluids in living organisms
  • Includes specialized conducting system (xylem and phloem) in vascular plants
  • Xylem functions as water conduits, storage, and mechanical support
  • Phloem functions as distributor of plant foods and nutrients
• Other types of tissues in the vascular system

  • Cambium gives rise to phloem on the outside and xylem on the inside, resulting in an increase in diameter
  • Pith is the innermost portion of the stele, a primary tissue found in stems and sometimes roots
• Growth Increments


  • Referred to as growth rings, growth increments, or annual rings
  • Composed of earlywood and latewood
  • Latewood is denser
• Sapwood-Heartwood Differences


  • Sapwood surrounds heartwood and is composed of living cells that conduct food and serve as storage
  • Heartwood is darker, dead, functions as mechanical support, and is more durable than sapwood
• Gross Features of Wood

  • Chemical Properties
  • Mechanical Properties
  • Physical and Moisture Relations Properties
  • Anatomical Properties
• Chemical Components of Wood

  • Carbohydrates: Cellulose, Hemicellulose
  • Lignin
  • Extraneous Compounds
• Physical Properties of Wood: Color


  • Properties exhibited due to extractives (polyphenols)
  • Varies across and within species
  • Color interpretation may be subjective due to discoloration attributed to decay or weathering and variations in individual interpretation of shades of colors
• Color


  • Properties exhibited due to extractives (polyphenols)
  • Varies across and within species
  • Color interpretation may be subjective due to discoloration attributed to decay or weathering and variations in individual interpretation of shades of colors
  • Light-colored woods are usually used for food supplements while dark-colored woods are ideal for decorative purposes
• Luster


  • The property of wood to reflect light
  • May be classified as lustrous or dull, or anything in between
  • Also related to the amount of extractives
• Odor and Taste


  • Some woods possess a distinct odor especially when fresh (emit free molecules into the air)
  • Some woods have distinct taste
• Texture


  • The size and proportional amount of cells in the woods as seen in the cross-section
• Weight


  • Varies according to amount of wood substance present per unit volume, amount of extractives, and according to moisture content
  • Examples of extremely heavy: malabayabas, extremely light: balsa
• Hardness


  • Determined by cutting a portion of wood with a knife/cutter or by applying pressure on the wood with fingernails
  • The more difficult it is to cut a portion of indent your nails the harder is the wood
• Grains


  1. Grain is straight when the alignment of cells is parallel to the longitudinal axis of the piece of wood

  2. Grain varies based on species, cut made, or whether or not the wood is figured
• Stress

  the measure of wood’s resistance to failure
• Strain


  the change in length due to distortion caused by stress
• Elasticity 


  the ratio of stress and strain of wood
• Vibration 


  ability of wood to transfer or dissipate energy when subjected to vibrations
• Cathedral grain

  pattern is easily identified by the loop or “cathedral” in the center with straighter grain along the edges. Cathedral grain is only produced in flat cut veneers
• Interlocked grain is produced by trees that grow spirally. Many tropical trees grow in this way and in some species, the spiral changes direction from year to year, producing an interlocked grain, noted for its light and dark patterns and lustrous surface. Most noticeable in quarter-cut veneers, this grain can produce ribbon stripes, mottles, curly, and fiddleback figures
• Irregular grain is produced when a tree swirls or twists in unexpected ways due to knots, burls, crotches, or branches
• Spiral grain is created naturally when a tree twists as it grows—due to stress, prevailing winds, obstacles, or other reasons. Wood fibers are oriented at an angle to the annual growth rings, creating a spiral pattern
• Straight grain pattern, as the name suggests, is pattern with lines that run parallel to each other and to the tree’s trunk
• Wavy grain pattern is produced when wood fibers run up and down the tree in a wavy pattern rather than in straight lines. A fairly rare pattern, it’s most clearly seen in flat cut veneers and often, but not always, results in a curly figure
• Coarse pore outlines are very distinct in the naked eye
• Fine pore outlines are not clearly visible to the naked ey
• Very Fine pore outline are clearly visible only with the aid of lens
• Discontinues Ring a ring that fails to develop
• False ring- excess rings produced during alternating poor and favorable conditions
• Ring porous - earlywood formed by large vessels which open at the beginning of the growing season
• Interlocked Grain is formed when two adjacent annual rings grow in opposite directions around the circumference of the stem
• Semi Ring Porous - earlywood formed by both large and small vessels which open throughout the growing season
• Diffuse Porous - earlywood formed by small vessels which open throughout the growing season
• Diffuse Porous - earlywood is composed of small vessels, tracheids, and fibers
• Spiral grain is caused by an irregular rotation of the tree trunk or branch as it grows
• Semiparallel Vessels - vessel elements arranged parallel to one another but not necessarily perpendicular to the growth axis
• Diffuse Porous - earlywood formed by numerous small vessels which open throughout the growing season
• Wavy grain - irregularities in the direction of growth