CIVE 2700 Lecture Notes - Lecture 16: Tracheid, Compressive Strength, Hemicellulose
4 Apr 2016
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Document Summary
Hardwood takes longer to grow, more expensive, not for construction. Architectural rather than for construction -- i. e. furniture. Civil engineering uses natural wood and engineering wood. 20 availability species used in canada; over 30 000 globally. Conifers grow in large strands and mature rapidly. I. e. short leaf pine, douglas fir, redwood, etc. Expensive - not used for structural purposes. I. e. black cherry, birch, oak, maple, etc. Anisotropic: strongest in the x-dinrection; r and t strengths vary slightly. Different species have different strength due to anatomical variations. Alive, not durable to decay, becomes heartwood over time. Pith - centre point (first year of growth) Produced by cambium in single growing season. In tropical regions (less seasonal change) - less different growth rings (indistinct) One ring doesn"t always show up as one year growth. Microstructure: wood is made up of millions of tubular cells bound together. Majority of cells oriented vertically in tree.
