Plants and People Lab – 6: Wood, Paper and Cushing Biology 328

Objective To study wood and its characteristics To study wood and its characteristics To learn how to make paper To learn how to make paper

Wood

The sequence of tissues from the center outward Pith Pith Primary xylem Primary xylem Secondary xylem Secondary xylem Vascular cambium Vascular cambium Secondary phloem Secondary phloem Primary phloem Primary phloem Phelloderm Phelloderm Phellogen Phellogen Phellem/Cork Phellem/Cork

The tissue sequence

Bark – Phloem (2 0 & 1 0) + Periderm Phellogen/cork cambium give rise to periderm (replaces epidermis) and produces Phellogen/cork cambium give rise to periderm (replaces epidermis) and produces Phellem/Cork (outside) Phellem/Cork (outside) Phelloderm (inside) Phelloderm (inside)

Wood – Secondary xylem Heartwood - old, non-functional xylem Heartwood - old, non-functional xylem Sapwod - new, water conducting xylem Sapwod - new, water conducting xylem (possess ray parenchyma cells to conduct water)

Hardwood and Softwood Hardwood – From angiosperms. Hardwood – From angiosperms. Xylem has both vessels and tracheids Softwood – From gymnosperms. Softwood – From gymnosperms. Xylem possess only tracheids

Tree Rings – Seasonal variations Spring wood/Early wood- Several large Spring wood/Early wood- Several large xylem cells, Lighter in color xylem cells, Lighter in color Summer wood/Late wood- Few xylem Summer wood/Late wood- Few xylem cells, Darker in color

Wood - Characteristics Porosity – Number of pores Porosity – Number of pores Density – Mass/Volume (Measured using oven dried wood of volume 1 cubic cm) Density – Mass/Volume (Measured using oven dried wood of volume 1 cubic cm) Grain - the structural arrangement of various wood elements Grain - the structural arrangement of various wood elements Figure - the design or pattern that appears on the surface Figure - the design or pattern that appears on the surface

XRT X – Cross section X – Cross section R – Radial (quarter-sawn) R – Radial (quarter-sawn) T – Tangential (Plain-sawed/slab-cut) T – Tangential (Plain-sawed/slab-cut) Knots Knots

Lumbering and Milling Veneer – Thinly sliced wood Veneer – Thinly sliced wood Plywood – Glued Veneers Plywood – Glued Veneers

Lumbering and Milling Particleboard – Made of saw dust and wood chips Particleboard – Made of saw dust and wood chips Fiberboard – Made of separated xylem elements Fiberboard – Made of separated xylem elements Charcoal – Wood burned in limited supply of oxygen Charcoal – Wood burned in limited supply of oxygen

Paper Separated plant fibers that have been matted together to form a sheet Separated plant fibers that have been matted together to form a sheet Plant fibers are separated Plant fibers are separated naturally by soaking and beating naturally by soaking and beating chemically by caustic alkali or sulphates chemically by caustic alkali or sulphates Fibers/cellulose is present along with Fibers/cellulose is present along with pectin in primary cell wall pectin in primary cell wall lignin in secondary cell wall lignin in secondary cell wall Pectin and lignin degrade and causing yellowing of paper Pectin and lignin degrade and causing yellowing of paper

Today’s lab Today’s lab Learn how to make paper? Learn how to make paper? Trip to Cushing library Trip to Cushing library

Paper strips Paper strips water water lye (caustic soda) lye (caustic soda) Mould and Deckle Mould and Deckle blender blender vat vat Materials required Materials required

Place 2-3 tablespoons of strips into a blender full of water and blend for at least 20 seconds. To size the paper fiber, add 1/5 teaspoon cold-water laundry starch with water and add to vat of pulp. In a large vat, place an amount of water and blended fibers. To form a sheet of paper, put the mould and deckle together and pull up from the bottom of the vat. Once the deckle is above the water level, gently shake side to side and front to back to interlock the fibers and to ensure an even sheet of paper. Invert this on a cloth and remove water from the back of the deckle with a sponge. The paper will now release from the deckle. Then, this can be dried between two cloths Method Method

Summary Today’s Lab Studied what wood and paper is, learned how to make paper, observed different types of books in Cushing Library Studied what wood and paper is, learned how to make paper, observed different types of books in Cushing Library Next week’s lab Field trip - Flora Field trip - Flora