Chapter 1-5 Flashcards
Benefits derived from the forest
Tangible and Intangible Benefits
Timber, pulpwood, firewood barks, tree tops, resin, gums, and wood oils, honey, beeswax, nipa, rattan, and other forest growth such as grass, shrub, and flowering plant, the associated water, fish, game scenic, historical, recreational and geologic
resources in the forest
Forest Products
Classification of Forest Products
Major Forest Products
Minor Forest Products
those products use in raw form
Primary wood products
those products that undergone further re manufacturing
Secondary wood products
these are non-wood products
Minor Forest Products
natural discharges of living trees and other forest growths
included by a natural or inflicted wound on the plant
Tree Exudent
a sticky flammable organic substance, insoluble in water, exuded by some trees and other plants (notably fir
and pine)
Resins
adhesive substance mostly obtained as exudate from the bark of trees or shrubs belonging to the family Fabaceae (Leguminosae)
Gums
a fluid transported in xylem cells (vessel elements or tracheids) or phloem sieve tube elements of a plant
Saps
a milky usually white fluid that is produced by cells of various plants
Latex
a natural plant product containing chiefly essential oil and resin (from the family Burseraceaee)
Oleoresins
chemically derived or reduced
Extracted Products
a natural or synthetic substance used to add color to or change the color of something
Dyes
a yellowish or brownish bitter-tasting organic substance present in some galls, barks and other plant tissues (from mangrove species, oak species, sakat and camatchile)
Tannins
obtained from pine species, distillation
of resin produce gum turpentine and gum resin
Naval stores
a natural oil typically obtained by distillation and having characteristic fragrance of the plant or other source from which it is extracted
Essential Oils
Other non-timber wood products
Abaca fibers, fruits, nipa shingles, medicinal plants, rattan, bamboo
any material derived from a forest for direct consumption or commercial use
Forest Products
FORESTRY CONTRIBUTION TO GDP
1-4 % of GDP
Significance of sustainable Forest Product Utilization
FOREST RESOURCES & POVERTY ALLEVIATION
STRATEGIES FOR A SUSTAINABLE USE OF WOOD
JOINT APPROACH
What does the forest can provide
Subsistence goods
Cash Income
Indirect Social and environmental benefits
A complex biological structure, a composite of many chemistry and cell types acting together to serve the
needs of a living plant
wood
It is a three dimensional, anisotropic and hygroscopic raw material which mainly composed of cellulose,
hemicellulose and lignin
wood
They are those woods that come
from gymnosperms (mostly conifers)
Softwood
they are generally needle-leaved evergreen trees such as pine (Pinus) and spruce (Picea)
Softwood
long cells that are often more than 100 times longer (1 – 10mm) than its width
Tracheid
major component of softwoods, making up over 90% of the volume of the wood
Tracheid
serve both the conductive and
mechanical needs of softwoods
Tracheid
oriented along the length of the tree-trunk, and are sometimes referred to as longitudinal or axial parenchyma
parenchyma
they are vertically oriented and stacked one on top of the other to form a parenchyma stand
axial parenchyma
much narrower and lack unique characteristics that are observable with a 10x hand lens, their usefulness in identification is essentially limited to
microscopic examination
Rays
sometimes referred to as resin
ducts, are unique to conifers
Resin canals
one of the apparent purposes of these ducts is to protect and seal up a wound by exuding resin to cover the damaged area of the tree
Resin Canals
they are typically broadleaf, deciduous trees such as maple (Acer), birch (Betula) and oak (Quercus)
Hardwood
appears to be holes in the wood
when viewed from the endgrain
pores
serves as the pipelines within the trunk, transporting sap within the tree (live tree)
Vessels
the largest type of cells, and unlike other hardwood cell types, they can be viewed individually – oftentimes
even without any sort of magnification
vessel elements
thin-walled storage units
parenchyma
long, tapered longitudinal cells,
brick shaped epithelium around
gum canals and ray cells
parenchyma
In radial view, _________ ____ cells are elongated horizontally
Procumbent ray
either squarish of vertically oriented
Upright Ray
saclike or crystal-like structures that
sometimes develop in a vessel and rarely in a fiber through the proliferation of the protoplast of a parenchyma cell through a pit pair
Tyloses
they commonly form in hardwoods as a result of wounding and effectively act to prevent water loss from the area around damaged tissues
Tyloses
they may also develop as a result of
infection from fungi or bacteria, again to prevent water loss
Tyloses
strong, thick cell walls that mainly
serve to support and strengthen the
trunk
Fibers
when viewed from the endgrain,
_______ are very small and can’t be
seen individually
fibers
can only be distinguished in a broader sense as colored areas which form the backdrop of the wood’s endgrain
fibers
it makes up the first 5 to 20 growth rings in a cross-section and is thought to be created in the cambium region
while it was still influenced by the apical meristem
Juvenile wood
are those harvested during maturity and usually found or obtained from the basal part of a log
Mature wood
found in some trees growing on
either level or sloping ground on a variety of soil types
Abnormal wod
are those without defects and
have low shrinkage and swelling
normal wood
found on the lower side of
leaning softwood trees
compression wood
found on the upper side of
leaning hardwood trees
tension wood
Unique Properties of wood
Hygroscopicity
Shrinkage and swelling
Mechanical Properties
Electrical Properties
Acoustic Properties
Biodegradable
wood can absorb water as a liquid, if
in contact with it, or as vapour from the surrounding atmosphere
Hygroscopicity
the theoretical point at which cell walls are completely saturated and cell
cavities are empty
Fiber Saturation Point
wood undergoes dimensional changes when its moisture fluctuates
below the fiber saturation point
Shrinkage
measures of its ability to resist
applied forces that might tend to
change its shape and size
Mechanical Properties
pulling force transmitted axially by
the means of a string, a cable, chain
or similar object
Tension
a force that squeezes something
together
Compression
wood is stronger when load is applied _______ to the _____ than _____ to the ____.
parallel to the grain than perpendicular to the grain
Wood is stronger in ________ than _____.
compression than tension
whenever forces act upon a body in such a way that one portion tends to slide upon another adjacent to it
Shear
often a design consideration
*Horizontal shear stress (parallel to the grain)
the resistance that the wood opposes to the transverse tensile stress before breaking due to the separation of its
fibers
Cleavage
the force per unit area acting on the material in an outward normal direction (pulling)
Tensile Stress
a measure of resistance to dents
and wear
Hardness
a range of numbers that determine
how dense a type of wood is and how resistant to dents, dings and wear
that a type of wood will be once installed
Janka Wood Hardness Scale
bending under a constant load or a
very slow applied load
Static Bending
dielectric or a very poor conductor of
electric current
wood
the separation of center of positive
charge and the center of negative charge in a material.
Electric polarization
wood is subject to __________ by bacteria, fungi,
insects, marine borers, and climatic,
mechanical, chemical and thermal factors
Degredation
ratio of the weight of water present in the wood to the weight of the wood that is completely dry
MOISTURE CONTENT
occurs as bound water is removed from the cell walls
Shrinkage
The volumetric shrinkage for most
wood species is typically within the
range of ___-__ (Meier, 2008)
9%-15%
occurs as wood gains moisture
below FSP
Swelling
the mass contained in a unit volume of the material, both measured
at the same moisture content
wood density
Density differs depending on the _____ __ _____ (cell wall) and ____ (cell lumen) present in the certain
volume of wood
extent of materials and voids
the ratio of the oven dry weight of a wood to the weight of a water volume equal to the volume of the wood at an identified moisture content such as green, air dry or oven dry conditions (Wood Handbook, 2010)
Specific gravity
why is specific gravity unit less?
since it is the ratio of two densities (ovendry density of wood and water
density)
the combination of ovendry weight and green volume of wood
Basic Specific Gravity
The density of water with a temperature of ______ is commonly used as reference to compute the specific gravity
4 degrees Celsius
Used to derive the SG of wood at various moisture contents when at least one specific gravity value at a certain moisture condition is given.
Browne’s formula
those that affect the performance
of the wood species and the ease
with which you can work with
MECHANICAL PROPERTIES OF WOOD
its fitness and ability to resist applied or external forces
MECHANICAL PROPERTIES OF WOOD
expressed as the ratio of the applied force divided by the resisting area
STRESS
Types of stress
Normal stress and Combined Stress
Types of normal stress
i. Tensile stress
ii. Compressive stress
Types of combined stress
i. Shear/Tangential stress
ii. Tortional stress
the pressure resulting from a force of one pound-force applied to an area of one square inch
psi
distortion or change in the shape and size of a body resulting from applied stress, expressed in terms of deformation per unit area or volume
strain
– ratio of increase in length to original length of the wood when it is subjected to a pull force
Tensile strain
ratio of decrease in length to original
length of the wood when it is subjected to a push force
compressive strain
ratio of change of volume of the
wood to the original volume
volumetric strain
strain due to shear stress
shear strain
resistance of a wood to the applied stress
STRENGTH OF MATERIAL
A measure of the flextural capability of
a piece of wood which determines its
fitness for use as beam such as for
rafters, floor joints, etc.
Bending strength
resistance of wood to forces that
tend to crush the member.
Compressive strength
The force applied to wood that shortens its dimension or reduce its volume
compressive stress
the compression force divided by the
cross-sectional area of the piece
being stressed
compressive stress
resistance of wood to forces that tend to pull section apart from the other.
Tensile strength
The force applied to wood that tend to
increase dimension or its volume
tension force
The measure of the ability of a material to resist forces that tend
to cause one of its part to slide or slip on another adjacent part
Shearing strength
Shear in wood is determined only in the direction _________ __ ____ ______.
parallel to the grain
the ability of the wood to withstand
suddenly applied force or load that exceeds the limit of proportionality
Toughness
the measure of resistance to
indentation, wear or scratches
hardness
often referred to as the strength-weight ratio, is defined as the ratio of strength to specific gravity. Reportedly used as an index to the measure of the efficiency of the wood to
resist stress
Specific Strength
the measure of the ability of the beam to support slowly applied load for a
short time
MODULUS OF RUPTURE
in bending, the magnitude of the load required to cause failure is expressed
by
modulus of rupture (R)
the measure of stiffness or rigidity which indicates the ability of material to recover its original shape and size
after the stress is removed.
MODULUS OF ELASTICITY
the modulus of elasticity of a beam is measure of its resistance to _______
deflection
CHEMICAL PROPERTIES OF WOOD
WOOD SUBSTANCES
EXTRANEOUS SUBSTANCES
the chemical components of wood
50% carbon, 6% hydrogen, 44%oxygen
insoluble in neutral solvents and non-volatile with steam also known as cell wall substance
WOOD SUBSTANCES
consists of cellulose, other polysaccharides (hemicellulose and pectin) and lignin substances
WOOD SUBSTANCES
it is an organic compound, and is the
skeleton of the cell wall, it constitutes about 40 to 50% of wood
CELLULOSE
they comprise 10 to 35% of cell walls
OTHER POLYSACCHARIDES
OTHER POLYSACCHARIDES
Hemi-cellulose
Pectin
it usually forms 1-2% and consists of a complex set of polysaccharides that are present in most primary cell
walls and helps to bind cells together
Pectin
it accounts for 20 to 35% of
the wood and fills the spaces in the cell wall between cellulose, hemicellulose and pectin components
Lignin
extractable by steam distillation of neutral solvents like acetone, alcohol, gasoline, water, benzene and
ether and can be organic or inorganic
EXTRANEOUS SUBSTANCES
they are either purely inorganic salts, including free silica, or salts of organic acids, and those form ash on burning
INORGANIC EXTRACTIVES
consists of the interventions applied to forests to maintain or enhance their utilization for specific purposes
Silvicultural practice or forest management practices
art and science of reproducing and
growing trees and forests in a sustainable manner based on principles of forest ecology for the benefit of society
silviculture
AIM of Silviculture:
enhance the growth and quality of
potential crop trees
A series of forestry practices using natural strategies to regenerate specific forest types according to landowner objectives.
silvicultural systems
an even-aged system where all or
nearly all of the trees are harvested
at one time
clearcutting
an even-aged system where one or two cuts are used prior to the final harvest. The first two cuts stimulate and establish advanced regeneration before the final harvest cut
SHELTERWOOD
Final crop in shelterwood should be:
a. windfirm
b. good species
c. undamaged by logging
an uneven-aged system where
trees of all sizes are harvested
on a cycle about 10-15 years.
SELECTION
any forestry practice not connected with regeneration or harvest
INTERMEDIATE TREATMENTS
cutting or culling of undesirable
species, usually in a sapling stand of
less than 4 inches in diameter
TIMBER STAND IMPROVEMENT
the removal of dead, damaged or susceptible trees, essentially to
prevent the spread of pests and
pathogens
SANITATION CUTTING
wood that has been processed as a
building material (board and planks)
lumber
used to collectively refer to
trees that have yet to be cut or processed
timber
synonymous to sawmilling
or lumbering, conversion of logs into
lumber
LUMBER MANUFACTURE
the processing plants used
in lumber manufacture
Sawmill
SAWMILL PARTS AND EQUIPMENT
Headsaw
Saw doctor
Resaw
Edger
Trimmer
used for the primary breakdown
of logs
Headsaw
person responsible for the
maintenance of the saw
Saw doctor
used in the further breakdown of large boards, cants or flitches and is usually installed in sawmill set-up with large output (>20, 000 bd.ft./day) or when
Resaw
used to cut boards into desired width and to remove defects along the edges of the lumber piece
Edger
single edger mounted on a rod
Single edger
two saws mounted on a rod where one is fixed while the other is adjustable
Double edger
used to cut boards or lumber into desired lengths
Trimmer
4 BASIC OPERATIONS IN LUMBER MANUFACTURE
HEADSAWING
RESAWING
EDGING
TRIMMING
breakdown of the logs into boards, flitches or cants
HEADSAWING
a flat, thin, rectangular piece of wood
which is used for a particular purpose
board
a piece of wood, either square edged or natural edged, that is one in a
sequence of matching pieces
Flitches
a portion of a log sawed on all
four sides
Cant
a sawing method to cut a log on all
four sides until the center of the log is
squared into a cant
Cant sawing
cutting a board into several thinner boards
RESAWING
cutting of lumber with parallel and
square sides to desired widths and
to remove wane irregular edges and
barks and other defects to improve
quality of the lumber
EDGING
cutting across the grain at the ends of
the lumber to the desired length
suitable for commercial use and to eliminate defects and render a balanced lumber grade
TRIMMING
METHODS OF SAWING METHODS OF SAWING
Taper sawing
Non-taper sawing
METHODS OF SAWING WITH RESPECT TO THE END GRAINS OF THE BOARDS
Plain Sawing
Quarter Sawing
Rift Sawing
sawing the log parallel to its outer axis
Taper sawing
sawing logs parallel to their central
axis
Non-taper sawing
sawing the logs more or less parallel with the growth rings thus the growth rings form an angle of about 0 – 40o with the wider surfaces of the board
Plain Sawing
sawing the logs more or less perpendicular to the growth rings thus the wider faces of the boards will be at 45 degrees to 90 degrees angle with growth rings
Quarter Sawing
both the most expensive and least common option on the market. The annular rings look best at 45 degrees but can fall anywhere between 30-60 degrees
Rift Sawing
TYPES OF LUMBER ACCORDING TO USE
Yard lumber
Structural lumber
Shop lumber
Outlumber
Form lumber
those generally used for buildings and
construction purposes; usually available in most local hardware stores
Yard lumber
lumber of large sizes or dimensions; mostly used for posts, piles, trusses,
beams and other heavy construction wood components
Structural lumber
smaller dimensioned for remanufacturing; commonly used for novelty wood items such as picture frames, craft boxes, containers, etc.
Shop lumber
trimmings and recovered lumber
wastes from sawmills (1” or less)
Outlumber
recycled, 2nd hand or used lumber (with nail holes) commonly used for
scaffoldings
Form lumber
TYPES OF LUMBER ACCORDING TO EXTENT OF MANUFACTURE
Rough lumber
Dressed lumber
Worked lumber
unplaned or with rough surfaces
Rough lumber
surfaces are smoothened or planed
Dressed lumber
those planed and re manufactured
further
Worked lumber
a joint made by a tongue on one edge of a board fitting into a corresponding groove on the edge of another board
tongue-and-groove
(TNG)
a step-shaped recess cut along the edge or in the face of a piece of wood, typically forming a match to the edge or tongue of another piece
rabbeted lumber
– decorative plane or curved strip used for finishing
mouldings
- Mini/Baby sawmill
- Small sawmill
- Medium sawmill
- Big sawmill
Based on Daily Rated Capacities
less than 10,00 bd.ft.
Mini/Baby sawmill
10, 000 to 20, 000 bd.ft.
Small sawmill
20, 000 to 40, 000 bd.ft.
Medium sawmill
more than 40, 000 bd.ft.
Big sawmill
According to type of headsaw used:
a. Circular sawmill
b. Band sawmill
c. Sash-gang sawmill
- uses large-diameter circular blades
Circular sawmill
- uses band saw with thinner saw bite
- a continuous wide steel band
with serrated teeth on one
side or on both edges
Band sawmill
- uses multiple gang headsaw which is consist of several reciprocating blade saws mounted on a frame or sash assembly
Sash-gang sawmill
SECONDARY SAWMILLING PROCESS
- SEASONING
- PRESERVATIVE TREATMENT
- SURFACING OR PLANING
- GROOVING
- GRADING & SORTING
- LUMBER PILING AND STORAGE
process of drying lumber to remove the bound moisture contained in walls of the wood cells to produced seasoned lumber
SEASONING
SEASONING
a. Air drying
b. Kiln drying
– fresh-cut lumber
piled in the lumber yard and
allowed to dry through air circulations/wind and/or sunlight
Air drying
– lumber are stacked in a chamber (kiln) where temperature, relative humidity and air circulation are controlled
Kiln drying
- treatment of the lumber with
chemicals or preservatives toxic or repellant to decay- causing organisms
PRESERVATIVE TREATMENT
- smoothening of the surface of the lumber by planers or sanders
SURFACING OR PLANING
- lumber for flooring and walls to facilitate joineries
GROOVING
- classification and segregation of
lumber according to size, species and quality of grades
GRADING & SORTING
In the Philippines, fuel wood is
sold by _____ measuring to
1mx1mx2m
talaksan
- are usually an abnormality or
irregularity in the wood that
arise from many different causes - it may be natural which occur
while the tree is growing or
artificial as a result of poor
conversion, seasoning or
handling after felling
WOOD DEFECTS
WOOD DEFECTS
- KNOTS
- CHECKS
- SPLIT (SHAKE)
- Warp
- BOXED HEART
- WANE
formed
when branches are broken
off or cut, and the exposed
wood is left behind.
KNOTS
- a crack which separates the
fibers of wood - it does not extend from one end
to the other - occurs across the growth
rings and usually is caused by
poor or improper drying
processes
CHECKS
- is a longitudinal separation of the fibers which extends to the opposite face or adjoining edge of a piece of sawn timber
SPLIT (SHAKE)
- any misshaping of a
board
Warp
Warp
a. CROOK
b. BOW (BOWING)
c. CUP (CUPPING)
d. TWISTING
e. DIAMOND (DIAMONDING)
- is the curvature of a piece of sawn timber in the plane of its wide face
CROOK
- the curvature of a piece of sawn timber in the direction of its length
BOW (BOWING)
- the curvature of a piece of sawn timber across its width.
CUP (CUPPING)
- is the spiral distortion of a piece of sawn timber; it may be accompanied by either bowing or spring, or both
TWISTING
- a distortion due to differential shrinkage in drying that causes a piece of timber originally square (or rectangular) in cross section to become diamond shaped
DIAMOND (DIAMONDING)
- a term used when the heart is enclosed within the four
surfaces of a piece of sawn timber.
BOXED HEART
- is the lack of wood on any face or edge of a piece of sawn timber, usually caused by a portion of the original rounded surface of a long remaining on the piece; bark may or may not be present.
WANE
- thin slices of wood and sometimes bark, usually thinner than 3mm (1/8 inch), that typically are glued onto core panels to produce flat panels such as doors, tops and panels for cabinets, parquet floors
VENEER
- an assembled wood product usually made up of two or more layers of veneer held together by adhesives, where the grains of adjacent layers are perpendicular to each other
PLYWOOD
