Biology 2241Z Lecture 8: 2217_lec5.pdf
Document Summary
Formed by herbaceous perennials and some annuals: wood is related to how plants grow in girth, accomplished by special meristems called cambia (sing: cambium) Cork cambium tissues to replace epidermis. New growth occurs as a sheath covering the main stem, branches and twigs. Many plants synthesize secondary walls after the cell has reached maturity (elongated) Secondary walls (cont. : bulk of woody plants, tracheary elements develop reinforced cell walls that can form a variety of patterns. Tree fights for water and sunlight against competing neighbours. Forest fire scars tree, but the damage is temporary. Outer portions clear lumber are made into boards or planks. This is made into heavier planks and beams. Hard, uniform wood: bowling pins and alleys, croquet mallets. Hard, dense, waterproof wood: used in barrels and some flooring. Softer, weather- resistant wood: used in railroad ties and water tanks. Hard, straight grained wood: used in baseball bats, tennis racquets, oars and tool handles.
