The Nature and Properties of Wood Flashcards
Are Hardwood or Softwood Considered Deciduous?
Hardwoods
Trees also identified as angiosperms?
Deciduous
What does angiosperms mean?
There seeds are covered
The Term Hardwood refers to a?
Biological Grouping
Hard woods are all not hard T or F
T
Ash, Oak and Maple are examples of Hardwoods or Softwoods?
Hardwoods
What is true about a hardwood trees structure?
They have a Dendritic structure which means that the main stem branches and debranches, continuously sub diving
General Characteristics of Hardwood trees?
- Broad leaves in various shapes and sizes
- Shed leaves in the fall at the end of each growing season
- Generally hard and durable, used for fine furniture
- Medullary ray cells can often be seen and the wood is closer grained than softwoods.
- Branches are larger than softwoods
-Tend to grow in warmer climates
Coniferous trees are hardwood or softwood trees?
Softwood
Also known as Gymnosperms?
Coniferous Trees
What does Gymnosperms mean?
Needle Bearing
Naked needle
Example of Softwoods?
Spruce
Fir
Pine
What does Excurrent structurein a tree refer to?
There is one main central stem with many smaller branches sticking out to the side
What kind of trees have an Excurrent structure
Coniferous trees Softwoods
Characteristics of softwoods?
- They have thin, round or semi flat needle-type leaves, bearing cones in which the seeds germinate and grow.
- Typically used in rough construction (Framing lumber)
- Medullary ray cells are invisible
- Frequently have dead knots and resin pockets
- Tend to grow in colder climates
Wood typically used in rough construction (Framing lumber)
Softwoods (Coniferous)
When strength is the main consideration it pays to choose a wood with a high?
Strength to weight ratio
Good indicator of a woods strength to weight ratio?
Density of Specific Gravity
If a given volume of a particular wood weighs the same amount as an identical volume of water, it is said to have a specific gravity of?
1.0
If a piece of wood weighs 60% of an identical volume of water it is said to have a Specific Gravity of?
0.6
Standard test for hardness?
Janka Hardness Test
__________ grain wood forms a more durable joint then ________ grain wood
Open grained wood forms a more durable joint than
Close grained woods
Compressive strength refers to?
load bearing capacity
Tensile strength refers to?
Resistance of the wood to forces trying to stretch it parallel to the grain
Wood is stronger in tension Parallel to the grain
What is the measurement that measures the ability of the wood to resist internal slipping parallel to the grain if one part is loaded more than another
Sheer resistance
What are the arrows pointing to top to bottom?
Cambium
Inner Bark
Outer Bark
Heartwood
Pith
Sapwood
Medullary Rays
Inner bark (Bast) layers job?
Transports food to the leaves downward from the leaves downward to the branches, trunk and roots
What is the cambium layer of a tree situated between?
Sapwood and inner bark where new growth occurs
Describe cells created on the inside and outer layer of the cambium
During the growing season, new sapwood cells(Xylem) are created on the inner side of this layer.
While new inner bark bast (Phloem cells) are created on the outside of the cambium layer
Outer portion of a tree trunk is
Sap Wood
What is the function of sapwood?
Acts as a conductor of sap up to the leaves and branches of the tree
Sap wood is an active layer where?
Food is stored and absorbed
Heartwood is typically lighter than sapwood T or F
F Sapwood is almost always going to be lighter
Inner portion of a tree trunk is called?
Heartwood
Heartwood gives what to a tree?
Stiffness and stability
In Heartwood the wood cells cease to conduct sap and they become darker in color from the infiltration of ?
Also known as Extractives
Gums
Resins
Oils
Tannin
Part of a tree more resistant to decay and insects
Heartwood
Furniture makers and veneer producers prize what part of the tree?
Heartwood
Hollow cells shaped like tiny tubes with close pointed ends? what is there function?
Tracheid’s
Fluid is transferred from one Tracheid to another through tiny opening in the side where the tracheid’s overlap
The tubes of Tracheid cells are largely made of?
Cellulous
Tubes or cells of Tracheid’s are cemented together with a material called
Lignin
Up to 95% of the cells in Tracheid’s are?
Softwoods
Runs horizontally, radiating out from the pith area towards the outside of the trunk?
Medullary Rays
Function of medullary rays
Stores and transfers food throughout the tree
Cant be seen in many softwoods but easier to see in hardwoods?
Medullary rays
Wood is comprised of ?
Cellulose
Hemicellulose
Lignin
Extractives
Chemical compound that gives wood its color, smell and oiliness or grittiness?
Extractives
Highly polymerized and complex chemical compound common in woody plants?
Lignin
If a board is Plain or Flat sawn the face grain is _______ and the edge grain is _______
Tangent
Radial
If a board is Quarter sawn the face grain is ?
Radial and edge grain is tangential
If a board is not clearly tangential or radial is is called?
Rift Sawn
What wood type of Sawn wood are the arrows pointing to left to right
Quarter sawn
Plain or Flat Sawn
Rift Sawn
Example of ring porous wood
Oak and Ash
What causes a woolly fuzzy surface?
Wood is machined with to high a moisture content
What kind of figure is this
Ribbon figure
What kind of figure is this
Curly or fiddleback Figure
What kind of figure is this
Stump
What kind of figure is this
Crotch
What kind of figure is this
Burl
What kind of figure is this
Birds eye
What kind of figure is this
Ray fleck or Flake figure (Left)
Rift Figure (Right)
What kind of figure is this
Flame
