Wood

Question 1

Softwood

Answer 1

• A type of tissue found in conifers

Question 2

Hardwood

Answer 2

• Only dicotyledon class of flowering plants

Question 3

Angiosperm

Answer 3

• Flowering plant

Question 4

Gymnosperm

Answer 4

• Conifers

- Cone-bearing seed plants

Question 5

Divisions of trees

Answer 5

• Angiosperms

- Gymnosperms

Question 6

Classes of Angiosperms

Answer 6

• Dicotyledon (eudicot)

- Monocotyledon

Question 7

What is wood made from?

Answer 7

• Accumulation of cell walls of the secondary xylem in conifers and dicot flowering plants

Question 8

What is Xylem and Phloem?

Answer 8

• xylem and phloem are vascular tissue
• Xylem conducts water upwards
• Phloem conducts organic constituents
• Can be secondary or primary

Question 9

What is secondary growth?

Answer 9

• In diameter of plant (girth)
• Cambium (lateral meristem)
• Produce phloem toward outside of plant, xylem toward inside
• Monocots don’t have secondary growth

Question 10

What is primary growth?

Answer 10

• Apical

- Produces leaves, non-woody stems, roots

Question 11

What is the accumulation of xylem tissue?

Answer 11

Wood

Question 12

Annual ring of xylem is what?

Answer 12

• Formed in one growing season
• Tree rings
• Dendrochronology to get age of tree by annual accumulation of xylem rings
• Springwood cells larger than later season cells

Question 13

Types of xylem cells

Answer 13

• tracheid cells, long and thin with tapered ends

- Vessel elements, short wide cells, align to form pipe-like vessels

Question 14

What happens when xylem cells form secondary cell walls?

Answer 14

• Cell walls harden with cell death

- Still work in conduction

Question 15

What type of xylem cells do conifers mostly have?

Answer 15

• Tracheid

- Makes wood more uniform

Question 16

What type of xylem cells do angiosperms mostly have?

Answer 16

• Dicots have more of both types

- Makes more variety wood

Question 17

Where does the property of wood come from?

Answer 17

• Lignification of secondary xylem walls

- Thickening of cell wall by lignin gives hardness

Question 18

Lignin

Answer 18

• Polymers of lignin subunits, many variations in final structure
• Phenolic compounds
• Up to 40% of plant organic material
• One of the most abundant organic substances in nature

Question 19

Importance of lignin

Answer 19

• Strengthens around fibrous polysaccharide cell wall
• Allows plant to become large, tall, upright structures
• Evolutionarily, adaptation of form in successful transition from aquatic to terrestrial habitat

Question 20

Why are there different types of wood?

Answer 20

• Polymerization of phenolic subunits is ‘random’
• Final polymers not uniform in result
• Wood from different sources have different characteristics

Question 21

What makes wood harder?

Answer 21

• More lignification

- Breakdown of random polymerization of subunits is difficult, makes wood durable

Question 22

BC temperate rainforest

Answer 22

• Few species of trees but large numbers of each (softwoods)

Question 23

Tropical rainforest

Answer 23

• Many diverse trees, interspersed (hardwoods)

Question 24

Where is the main source of hardwood in the world?

Answer 24

• Tropical Asia

Question 25

Bark

Answer 25

- Phloem and protective covering layer, periderm | - Periderm expands as plant grows in girth

Question 26

Cork

Answer 26

- Major part of periderm | - Useful for special properties

Question 27

Special properties of Cork and what is Suberin?

Answer 27

- Air-filled principally dead cells - cell walls contain suberin, - Suberin is a Complex polymer of phenolics and long hydrocarbon chains, A Waxy component - Impermeable, buoyant, elasticity - No synthetic contains all these properties

Question 28

What do the special properties of cork do for the plant?

Answer 28

- Physical protection, insulation, and fire protection

Question 29

What are uses for cork?

Answer 29

- Wine stoppers - Gaskets - Badminton shuttlecocks - Flooring - Acoustic and thermal insulation - Bulletin boards

Question 30

History of paper

Answer 30

- Plant fibres into paper first developed by Chinese, documented in year 105 from bark of mulberry tree - Didn't reach Europe for 1000 years - Paper rare and valuable in history

Question 31

What is a major product of Canadian forestry?

Answer 31

- Wood pulp paper

Question 32

Wood pulp paper technology developed when?

Answer 32

- late 19th century

Question 33

What kind of wood is suitable for paper?

Answer 33

- Conifer, softwood | - Uniform tracheid cells

Question 34

How is wood pulp paper made?

Answer 34

- Wood stripped of bark and chipped | - Chemical or mechanical process

Question 35

What is the mechanical process for producing paper?

Answer 35

- Simple grinding - Slurry washed, screened, and pressed - Cheap quality, yellow, and degrades

Question 36

What is the chemical process for producing paper?

Answer 36

- Cook in digester to dissolve lignin - Harsh acid or alkali treatments to dissolve other components like resins - Bleaching and texturizing agents for white and quality paper

Question 37

What are some of the environmental impacts of paper production?

Answer 37

- Uses energy and strong chemicals - 40-50% of worlds industrial logging is for paper - Pulp and paper industry responsible for 4% of world energy use - Polluter of air and water

Question 38

Has digital documentation and electronic communication resulted in a reduction of paper use?

Answer 38

- No | - But paper going into landfills has been declining since 2000

Question 39

How much of Canada's waste does paper account for?

Answer 39

one third

Question 40

What is the single largest category of paper use?

Answer 40

- Packaging accounts for 41% of all paper used