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
