Timber

Question 1

volume of wood used is

Answer 1

less that volume of wood grown

Question 2

what percent of wood is carbon

Answer 2

50%

Question 3

CO2 + H2O ->

Answer 3

C6H12O6 + O2

Question 4

softwood forests are

Answer 4

coniferous/evergreen

Question 5

hardwoods forests are

Answer 5

deciduous/broad-leaved

Question 6

which wood grows faster

Answer 6

softwoods generally grow faster than hardwoods

Question 7

what species of timber does the timber industry rely on worldwide to build in construction

Answer 7

softwood species provide the bulk of timber used in timber construction

Question 8

when are hardwoods used

Answer 8

in limited cases

Question 9

which wood is cheaper

Answer 9

softwoods

Question 10

what is the part of wood on the outside layer called

Answer 10

outer bark (dead)

Question 11

what is the part of wood inside the outside layer called

Answer 11

inner layer (living)

Question 12

what is the part of wood inside the inner layer called

Answer 12

cambium

Question 13

what is the part of wood called spanning the outer layer inside the cambium

Answer 13

sapwood

Question 14

what is the part of wood spanning the inside of sapwood

Answer 14

heartwood

Question 15

what is the middle of the wood called

Answer 15

pith

Question 16

what are the directions of wood called

Answer 16

wood rays

Question 17

what part of wood participates in sap conduction

Answer 17

sapwood, not heartwood

Question 18

what wood is lighter and not resistant to fungi

Answer 18

sapwood

Question 19

what wood is more resistant to fungi and difficult to treat and more stable in changing moisture conditions

Answer 19

heartwood

Question 20

are there differences in structural properties between sapwood and heartwood

Answer 20

no

Question 21

light bands are

Answer 21

earlywood

Question 22

dark hands are

Answer 22

latewood

Question 23

summerwood cell properties

Answer 23

densely packed, thicker cell walls, higher density

Question 24

radial and tangential are called

Answer 24

traverse

Question 25

what are the longitudinal direction of wood grains called

Answer 25

parallel to grain

Question 25

why is flatsawn used more than quartersawn

Answer 25

because you get a lot more material produced from each log

Question 25

EL: ER: ET ≈

Answer 25

20 : 1.6 : 1

Question 26

why is quartersawn used less then flatsawn

Answer 26

because its expensive to buy and theres risk of less material

Question 27

what are the positives of quartersawn

Answer 27

better moisture fluctuation resistance and stability

Question 28

what are the negatives of flatsawn

Answer 28

risk of deformation

Question 29

what is the single most important indicator of strength in wood

Answer 29

density

Question 30

what is density related to

Answer 30

hardness, ease of machining and nailing resistance

Question 31

what is specific gravity of timber

Answer 31

ratio of density of wood to the density of water using oven-dry weight and current volume

Question 32

what is a defect in wood

Answer 32

any feature that alters the natural grain of the wood

Question 33

what are different defects in wood

Answer 33

knots, slope of grain, resin pocket, check, split, compression wood, and wane

Question 34

what occurs as a result of changes in moisture

Answer 34

check and split

Question 35

when are defects critical

Answer 35

when there are knots in tension zones or split/check in connection area

Question 36

what are knots

Answer 36

remnants of the branch connections on the trunk, can be "tight" (packed in) or 'loose' (pop out) and can be very dense

Question 37

how to increase the quality of wood and its value

Answer 37

branches are cut regularly to minimise knots

Question 38

90% of all problems with wood involve

Answer 38

moisture

Question 39

why are wood in trees very wet

Answer 39

because the cell structure contains excessive water (sap) and is fully swollen

Question 40

when wood is used the water will

Answer 40

dry out and partially shrink

Question 41

what will be reached eventually for wood moisture

Answer 41

the moisture balance between the dryness of the wood and the humidity of its environment will bereached

Question 42

what determines the moisture content of the wood

Answer 42

atmospheric humidity

Question 43

wat determines the dimensions of the wood

Answer 43

moisture content of the wood

Question 44

how to calculate moisture content %

Answer 44

weight of water/weight of oven dry wood x 100/1

Question 45

what is humidity referred to

Answer 45

water or moisture in vapour form in the atmosphere

Question 46

what is relative humity

Answer 46

the ratio of the amount of moisture in the air at a certain temperature to the amount it would be able to hold at that temperature

Question 47

how does wood remain

Answer 47

hygroscopic

Question 48

what does hydroscopic mean

Answer 48

responds to changes in atmospheric humidity and loses bound water as the relative humidity drops and regains bound water as relative humidity increases

Question 49

when wood is no longer gaining or losing moisture, wood is said to have reached its

Answer 49

equilibrium moisture content

Question 50

what is air-dry wood

Answer 50

wood which moisture content is in equilibrium with the ambient air relative humidity

Question 51

what is kiln-dried wood

Answer 51

wood which moisture content has been reduced to about 15-19% (it can still gain moisture)

Question 52

whats bow shrinkage letter

Answer 52

w

Question 53

whats spring shrinkage letter

Answer 53

x

Question 54

whats twist shrinkage letter

Answer 54

y

Question 55

wats cup shrinkage letter

Answer 55

z

Question 56

in protected areas, the moisture content varies from ? in unheated areas

Answer 56

14-18%

Question 57

in protected areas, the moisture content varies from ? in heated areas

Answer 57

8-12%

Question 58

change in dimension due to moisture content is calculated from

Answer 58

(% shrinkage)/100 x (change in moisture content)/(fibre saturation point -12) x (initial dimension)