Bcn1210 Test 3 Review - Wood – Ch 13

Front 1

The term ____ applies to wood products derived directly from logs.

Back 1

Lumber

Front 2

Only ____ of wood are classified as lumber.

Back 2

Solid pieces

Front 3

The terms lumber, ____, ____, and ____ are used synonymously.

Back 3

Solid lumber, solid sawn lumber, and sawn lumber

Front 4

Wood is a fairly durable material, provided it is protected from ____ and ____.

Back 4

Fire and biological destruction

Front 5

Name some advantages of wood and other structural materials.

Back 5

1. High strength-to-weight ratio (reduces dead loads and eliminates need for heavy equipment)

2. Lower cost

3. Simple construction techniques

Front 6

In countries with abundant forest reserves, wood is used extensively for ____ and ____ buildings.

Back 6

Residential and low-rise commercial

Front 7

A tree consists of 3 essential parts:

Back 7

1. root structure

2. trunk

3. branches and leaf system

Front 8

In a cross section through the trunk of a tree, what are the names of the different parts/sections?

Back 8

Bark, cambium layer, heartwood, and sapwood

Front 9

Describe the cambian layer.

Back 9

The area where cell division takes place, lies between the bark and outermost growth ring in the cross section through the trunk.

Front 10

Describe the heartwood area.

Back 10

The interior dark-colored region of the trunk.

Front 11

Describe the sapwood area.

Back 11

The light-colored region of the trunk.

Front 12

The cells added during the wet and dry seasons are called:

Back 12

Wet season – earlywoodDry season – latewood

Front 13

Describe the appearance of earlywood and latewood.

Back 13

Earlywood – rings are lighter and thickerLatewood – rings are darker and thinner

Front 14

The distinct growth rings give wood its characteristic ____.

Back 14

Grain structure

Front 15

The change from sapwood to heartwood is____, and as a tree ages, the heartwood portion in the tree____.

Back 15

Gradual; increases

Front 16

Heartwood of most commercial trees is relatively more ____ than the sapwood.

Back 16

Decay-resistant

Front 17

Contemporary building codes recognize the decay resistance of the heartwood of redwood and cedar by allowing them to be used where ____ is required.

Back 17

Pressure-treated wood (the use of PT wood is more common due to its greater decay/termite resistance)

Front 18

Lumber is divided into two broad categories:

Back 18

Hardwoods and softwoods

Front 19

List the characteristics of softwood producing trees.

Back 19

1. Generally, do not bear flowers

2. Have single main stem

3. Most are evergreens, with leaves that are needle-like

Front 20

List the characteristics of hardwood producing trees.

Back 20

1. Generally flowering trees

2. Have broad leaves

3. Typically deciduous, shedding and re-growing leaves annually.

Front 21

T/F. Softwoods can be denser than hardwoods.

Back 21

True. Slash pine and longleaf pine are softwoods, but are denser than many hardwoods. (Source: Page 264Figure 13.8)

Front 22

Name four species from the Southern Pine Region.

Back 22

Longleaf pine, shortleaf pine, slash pine, loblolly pine (Source: Page 266, Figure 13.11)

Front 23

In softwood, the light-colored region (aka ____) has ____ cell cavities and ____ walls of a growth ring.

Back 23

Earlywood, larger cell cavities, thinner walls

Front 24

In softwood, the dark-colored region (aka ____) has ____ cell cavities and ____ walls of a growth ring.

Back 24

Latewood, smaller cell cavities, thicker walls

Front 25

A magnified view of a hardwood’s growth ring, shows it has a more ____ than that of softwood.

Back 25

Complex microstructure

Front 26

Define “isotropic”.

Back 26

Having the same properties in all directions (steel, concrete).

Front 27

Define “anisotropic”.

Back 27

Not having the same properties in all directions (wood).

Front 28

A piece of lumber is much stronger ____ than ____.

Back 28

Along the grain (parallel to axis of cells); across the grain (perpendicular)

Front 29

The conversion process of logs to finished lumber consists of what 4 basic steps?

Back 29

1. Transportation of logs from forest to mill

2. Debarking of logs

3. Sawing the debarked logs into lumber

4. Surfacing lumber members smooth

Front 30

What are the 2 common methods used for sawing logs?

Back 30

1. flat (or plain) sawing

2. radial (or quarter) sawing

Front 31

Flat sawing of a large diameter log in two directions yields several pieces of ____ and ____.

Back 31

Dimensional lumber and timber

Front 32

When flat sawing a small diameter log, sawing may be along one dimension only, giving primarily ____.

Back 32

Dimension lumber

Front 33

____ sawing is more wasteful of wood than ____ sawing.

Back 33

Quarter/radial more wasteful than flat/plain

Front 34

In a quarter-sawn piece, the growth rings are ____ to its wider faces.

Back 34

Perpendicular

Front 35

Lumber must be dried aka ____.

Back 35

Seasoned

Front 36

____ implies a controlled rate of drying which minimizes the separation of fibers during the drying process.

Back 36

Seasoning

Front 37

How is the moisture content (MC) in a piece of wood calculated?

Back 37

MC=(weight of water in wood/weight of oven-dry wood) x100 *expressed in %

Front 38

What are the 2 types of water in wood?

Back 38

1. Free water – cavity water

2. Bound water – cell water

Front 39

The stage at which all the free water has evaporated and the bound water has just begun to evaporate is referred to as ____.

Back 39

Fiber saturation point (FSP)

Front 40

At the point of fiber saturation point (FSP) the cell walls are in their fully ____, just as they were when there was ____ water in the cells.

Back 40

Saturated point; free-water

Front 41

Lumber is typically seasoned in a mill to a moisture content of ____.

Back 41

19% or less

Front 42

How is dry lumber distinguished from green lumber?

Back 42

Dry lumber (MC less than or equal to 19%)

Green lumber (MC greater than or equal to20%)

Front 43

How is dry and green lumber identified?

Back 43

Surface dry (S-DRY) and surface green (S-GRN)

Front 44

Lumbers marked ____, ____, or ____ are considered to be equivalent for most structural purposes.

Back 44

S-DRY, MC 15, or KD 15

Front 45

Wood shrinks only ____ the grain, not ____ the grain.

Back 45

Across the grain, not along.

Front 46

The shrinkage and swelling are much larger ____ the direction of growth rings in lumber (____ direction) than ____ the direction of growth rings (____ direction).

Back 46

Along the growth, tangential direction; perpendicular to growth, radial direction

Front 47

Quarter sawn lumber ____, and tangentially (flat) sawn lumber will generally ____ when drying.

Back 47

Shrinks uniformly; cup, bow, or twist

Front 48

Because of its ability to dry uniformly, ____ sawn lumber is preferred for wood flooring.

Back 48

Radially (quarter) sawn

Front 49

Why does seasoning usually precede surfacing?

Back 49

Surfacing (done by high-speed planning machines) smooths lumber, rounds off edges, removes distortions that occurred during seasoning.

Front 50

Lumber that has been surfaced before seasoning is identified as ____.

Back 50

S-GRN (surfaced green)

Front 51

What does S4S mean?

Back 51

Surfaced 4 sides

Front 52

What does S1S2E mean?

Back 52

Surfaced 1 side, 2 edges

Front 53

By ____, defects in a wood member are cut away and the good pieces are joined to obtain higher-grade lumber.

Back 53

Finger jointing

Front 54

T/F. Because of high-strength and water-resistant glues, a finger jointed member is as strong as a single length (unjointed) member.

Back 54

True

*they can also be used interchangeably

Front 55

What is an easy way to remember nominal (call) dimensions and actual dimensions?

Back 55

Under 2” (subtract ¼”)

> or = 2”, 2”-6” (subtract ½”)

> 6” (subtract ¾”)

Front 56

What are the dimensions of 1 board foot (bd ft)?

Back 56

1’x1’x1” *1 cubic ft lumber

(1’x1’x1’=12 bd ft)

Front 57

What are the 3 categories of lumber?

Back 57

1. board lumber, or boards (less than 2” thick)

2. dimension lumber (2-4” thick)

3. timbers (5+” thick)

Front 58

Most of the lumber used in structural framing of wood buildings is ____.

Back 58

Dimensional lumber

Front 59

If a member thicker than 2” is required, 2 or 3 2-by members can be ____.

Back 59

Nailed, screwed or bolted together

Front 60

Dimension lumber is available in lengths of ____.

Back 60

8’, 10’, 12’, and so on, in steps of 2’ up to 28’

Front 61

An important factor that affects the strength of lumber is the _____.

Back 61

Slope of the grain

(parallel w/grain=max strength; slope of grain in respect to axis increases, strength decreases)

Front 62

A ____ occurs where a branch emerges from the tree trunk.

Back 62

Knot

Front 63

A knot in a member ____ its strength.

Back 63

Reduces.

**More knots=less strength

Front 64

A ____ knot reduces strength substantially and knot is rotting, it results in a ____. A knot that is not loose, but tightly intergrown is called a(an) ____.

Back 64

Loose knot, knot hole; enclosed knot

Front 65

___, ___, and ___ are separations of wood fibers.

Back 65

Checks, shakes, and splits

Front 66

A check is separation of wood fibers along the ____.

Back 66

Along the rays (perpendicular to growth rings)

*caused by drying, surfaces dry faster than interior

Front 67

A shake is separation of wood fibers along the ____.

Back 67

Growth rings

*occurs during growth of tree, not drying

Front 68

A split occurs ____ and is a complete ____.

Back 68

At the ends of members; complete separation of wood fibers through entire end.

*occurred during growth, aggravated by drying. Shake (or check?) that dried too fast

Front 69

A ____ is the absence of wood or presence of bark at the corner or edge of a piece that results from the sawing process.

Back 69

Wane

Front 70

Name 5 characteristics of wood that reduces the strength and is therefore considered when grading the lumber.

Back 70

Knots, checks, splits, shakes, and wanes

Front 71

Grading of lumber is done by ____ which employs trained inspectors.

Back 71

Independent inspection agency

Front 72

Grade stamps on lumber identifies the following items:

Back 72

1. species of lumber

2. moisture content at time of surfacing

3. the mill that produced the piece

4. inspection (grading) agency

5. structural grade

Front 73

Whereas the lumber used in the structural frame of a typical wood building is visually graded, the lumber used in more demanding applications (e.g. wood trusses) is ____.

Back 73

Machine graded

Front 74

Machine graded lumber is referred to as ____ or simply ____.

Back 74

Machine stressed rated lumber (MSR) or machine-rated lumber

Front 75

____ is caused by living organisms that use wood as food. Two groups of organisms consume wood ____ and ____.

Back 75

Biodeterioration; fungi and insects

Front 76

Because fungus is a plant life, 4 factors are necessary for survival/growth:

Back 76

Oxygen, mild temp, water, food

Front 77

2 options available to prevent decay of exposed wood:

Back 77

1. use naturally decay-resistant species

2. use preservative-treated lumber (e.g. when in contact with ground/foundation)

Front 78

Ways to reduce/prevent termite damage:

Back 78

1. maintain distance between wood/ground

2. provide soil barrier, a chemical soil treatment

3. use naturally decay-resistant or PT wood

4. use termite shield5. inspection/remediation

Front 79

The use of a ____ is recommended as additional protection in regions with heavy infestations of termites.

Back 79

Termite shield

Front 80

____ is the most effective/common method of termite protection

Back 80

Preservative treated lumber (or pressure treated)

*PT lumber resist insect and fungal attacks