Industrial Techniques

• Trees


  Primary source of lumber used in several instances, particularly in buildings and furniture
• What are Trees?


  Trees are the primary source of lumber which is used in several instances for example it is one of the earliest materials to be used in buildings. It is still used as a major part in general building, particularly in furniture building.
• Main Divisions of a Tree

  • Root
  • Trunk
  • Crown
• Root


  1. Provide anchorage for the tree

  2. Absorb water and minerals

  3. Store food for the tree
• Trunk


  1. Main source of lumber

  2. Backbone/Spine of the tree (rigidity and mechanical strength)

  3. Support for the crown
• Crown


  1. Produces plant food (manufacturing center) for the tree through photosynthesis

  2. Provides shelter

  3. Beautifies the tree
• Structure/Cross-Section of a Tree

  • Bark
  • Inner Bark/Bast
  • Cambium Layer
  • Sapwood
  • Heartwood
  • Pith
  • Annual Rings
  • Medullary Rays
• Bark


  Rough outermost layer that protects the tree from insects, bacteria, fungal attack and evaporation from sunlight
• Inner Bark/Bast


  Second layer which assists in transporting plant food from the leaves to the rest of the tree
• Cambium Layer


  Third layer consisting of two types of cells, bast cells on the outer and sapwood cells on the inner portion
• Sapwood


  Outer, new wood cells responsible for the growth (girth) of the tree, normally softer and lighter in colour than the heartwood
• Heartwood


  Inner wood that is considered the old wood, often times harder due to dead cells, darker in colour and drier than the sapwood
• Pith


  Innermost layer and the oldest part of the structure that over a period of time rots and leaves the tree hollow
• Annual Rings


  Concentric rings which separate each layer and are useful in telling the approximate age of the tree
• Medullary Rays


  Tangential lines/cells travelling from the pith through to the bast/inner bark transporting plant food from the bast to the various layers within the structure
• Categories of Trees


  Hardwoods<|>Softwoods
• Hardwoods


  Broad-leaved trees that have leaves actually wider than their length, with seeds enclosed within the fruit, found in tropical or sub-tropical climates
• Hardwood trees can either be Deciduous or Evergreen
• Softwoods


  Coniferous (cone bearing) trees that have needle-like leaves and are usually evergreen, with seeds not enclosed in the fruit, found in cool or cold climates