Physical Properties of Wood

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Physical Properties of Wood

• Tensile Strength
• Compression Strength
• Splitting Strength

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Biological Properties Xylem

• Conducts water and minerals from soil upward
• gymnosperms
• Tracheids
• Softwoods, e.g. pine, spruce, cedar
• angiosperm
• Tracheids
• Vessel elements
• Hardwoods, e.g. maple, oak, mahogany

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Fig. 38.13a
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Stems Secondary growth

• Vascular tissue, (xylem) makes up the bulk of the
  stem
• Form tree rings

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Example Gymnosperms
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Example Angiosperms
Brazilian Rosewood
African Mahogany
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Links to Other Resources

• For those of you who asked for more information,
  the Guild of American Luthiers (luth.org below)
  is a great resource. Note wood suppliers, and
  harp-making links are on that page, for those who
  asked.
• http//www.luth.org/
• http//www.luth.org/hot.htm
• http//www.frettedinstrumentguildofamerica.org/pag
  es/872009/index.htm
• http//www.violadabraccio.com/
• http//www.cs.dartmouth.edu/lsa/index.html
• http//www.folkharpsociety.org/index.html

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Cork

• Characteristics due to many air-filled cells,
  good insulating material, lightweight, floats
• Cork cambium develops within the secondary phloem
• Quercus suber - cork oak

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What is paper?

• Paper derives from the word "papyrus
• paper includes a wide range of products with very
  different applications communication, cultural,
  educational, artistic, hygienic, sanitary as well
  as storage and transport of all kinds of goods.
  It's almost impossible to imagine a life without
  paper.
• The best paper is pure cellulose

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Paper trivia

• Each American uses about 144 pounds of paper per
  year!
• more than 500,000 trees per week are used to
  produce the 2/3 of newspapers that are never
  recycled
• every ton of paper that is recycled saves 17
  trees, 7,000 gallons of water, 4,100 kilowatts
  of electricity
• producing paper from recycled fibers reduces air
  pollutants by as much as 74 and water pollutants
  by as much as 35
• every ton of paper recycled leaves 3.3 cubic
  yards of free space in landfills

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Historical writing surfaces

• papyrus (Cyperus papyrus, Cyperaceae) - Egyptians
• rice paper (Fatsia papyrifera, Araliaceae) -
  Orient
• mulberry paper (Broussonetia papyrifera,
  Moaraceae) - Mayans

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Paper

• separated plant fibers that have been matted
  together to form a sheet
• true paper
• thin sheets must be made from fiber that has been
  macerated until each individual filament is a
  separate unit
• fibers are then intermixed with water, and, by
  the use of a sieve like screen, are lifted from
  the water in the form of a thin stratum, the
  water draining through the small openings of the
  screen leaving a sheet of matted fiber upon the
  screen's surface
• This thin layer of intertwined fiber is paper

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Making Paper

• Harvesting
• Cooking with lye
• Rinsing
• Beating or blend to make pulp
• Add laundry starch to size
• Mould and Deckle
• http//www.missioncreekpress.com/plants.htm

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Bamboo

• No secondary xylem, primary growth only
• Segmented, hollow tubes, typical grass stem
• Used for fishing poles, caning for furniture,
  house construction in tropics, skyscraper
  scaffolding in Japan
• Pandas feed on young leaves stems of bamboo
• Bamboos have unusual life cycle, some species
  grow for decades without flowering, then all the
  members of a species worldwide will flower and
  die the same year