2. What are we going to explore?
A brief introduction on trees
The Life Cycle of trees
How to identify the various types
The log- lumber- timber connection
Formation of wood
Classification of Trees
Properties of wood
Commercial usage of wood
Classification of wood
Defects in wood
A look into different wooden samples
Preservation of wood
Exterior usage of wood
Interior usage of wood
• Wood is a porous and fibrous structural tissue found in
the stems and roots of trees and other woody plants. It
has been used for thousands of years for both fuel and
as a construction material.
• It is an organic material, a natural composite of
cellulose fibers (which are strong in tension) embedded
in a matrix of lignin which resists compression.
• Wood is sometimes defined as only the
secondary xylem in the stems of trees, or it is defined
more broadly to include the same type of tissue
elsewhere such as in the roots of trees or shrubs.
• In a living tree it performs a support function, enabling
woody plants to grow large or to stand up by
themselves. It also mediates the transfer of water
and nutrients to the leaves and other growing tissues.
• Wood may also refer to other plant materials with
comparable properties, and to material engineered from
wood, or wood chips or fibre.
• The Earth contains about one trillion tonnes of wood,
which grows at a rate of 10 billion tonnes per year.
• As an abundant, carbon-neutral renewable resource,
woody materials have been of intense interest as a
source of renewable energy.
• In 1991, approximately 3.5 cubic kilometres of wood
were harvested. Dominant uses were for furniture and
4. Where do trees grow?
• Trees grow at the
desert. They also grow
at home. Trees can
grow where ever you
go. They grow at the
forests where they are
all together. Trees also
grow at the jungle,
parks and and at home.
5. Lumber or timber is a collective term for harvested wood that has been manufactured
into boards and planks. This process is part of something called wood production.
Lumber is predominantly used for structural purposes but has many other uses as
well. Lumber is classified as hardwood or softwood.
India with the Russian
Federation, Brazil, Canada,
United States of America,
Republic of the Congo,
Australia, Indonesia and
Sudan account for 67
percent of total forest
area of the world.
6. Why do trees have different shapes?
• Some trees are different
shapes cause some live
in dry places and some
do t . T ees a e
different shapes cause
some are biased and
some are not.
7. How many kinds of trees are there?
• There is 100,000 types
of trees in the world.
8. Explain the life cycle of a tree.
• First you plant a seed
then it grows into a
seedling. Then the
seedling turns in to a
tree. After that the tree
grows flowers then the
flowers grow in to fruit.
9. How do trees feed?
• The sun shines on the
leafs then the
inside it then it makes
food for the tree.
10. Name and describe the parts of a tree.
• Trunk – A trunk is huge
• Leafs –Leafs good helpers
cause they get food for the
• Branches- Braches are
strong they grow leafs.
• Roots –Roots hold up the
tree and it is really good.
• Flowers- Flowers make
more seeds to grow trees.
11. Describe the skin of a tree and its purpose.
• The skin of a tree is
called bark and it
protects the inside of
the tree. trees skins are
wrinkly and they are
15. How do trees stand up?
• Trees stand up by their
strong roots that are
underneath the ground.
16. How old can a tree be?
• A tree can be over 4000
17. How can you tell the age of a tree?
• You can tell by the rings
when you cut it down.
How wide the tree is
tells you how old a tree
can be when it is still
19. Advantages of Timber
• Environmentally friendly
• Good appearance, aesthetic
• Low weight to strength ratio
• Light, easy to handle, easily
• Suitable for prefabrication of
components (reduce amount of
20. • Wood floats on water.Low density
• Wood absorbs water and it
PROPERTIES OF WOOD
• Ductility: It can be moulded into threads.
• Malleable: It can be moulded into sheets.
• Tenaciousity: It does t break with hits..
• Electric insulator
• Acoustic insulator
• Thermal insulator
22. PROPERTIES OF WOOD - MECHANICAL
Tensile Strength – Ti e is st o ge i te sio alo g the ai ut it s uite
difficult to determine this because of the difficulties in conducting test.
Compressive Strength – The strength along the grain is important for
columns, props, and post.
Shear Strength – Shear strength is important in the case of the beam and
Bending Strength or Flexural Strength – This refers as the strength of the
timber as a beam.
Cleavability – High resistance for cleavage is important for nailing and
screwing while low splitting strength is important for used as firewood.
Brittleness – is use to describe the property of suffering little deformations
Torsion Strength – is used to determine the torsion strength of the timber
and the specimen is loaded up to failure.
Hardness – is important in case of timber for paving blocks flooring
bearings and other similar purposes.
Stiffness - This property is important to determine the deflection of a
23. PROPERTIES OF WOOD
A measure of the rate of heat flow (W m–2 or Btu h–1 ft–2)
through a material subjected to unit temperature difference
(K or °F) across unit thickness (m or in.)
The amount of energy needed to increase one unit of mass
(kg or lb) one unit in temperature (K or °F)
A measure of how quickly a material can absorb heat from its
Coefficient of Thermal Expansion
A measure of the relative change of dimension caused by
25. UNDESIRABLE CHARACTERISTICS OF WOOD
• Not perfectly straight nor precise
• Size & shape affected by moisture
• Contains growth defects
• Can spilt & warp
• Burns easily
• Susceptible to Insect Damage
26. Classification of trees
Coniferous trees generally have narrow, hard leaves that are
known as scales or needles, depending on their shape.
Nearly all of them are evergreen.
Conifers do not have true flowers; instead, they produce cones.
45. Dowel Joint
• Do els o e i diffe e t sizes ¼”, 3/8”, ½” , /8” et .
• These joints are hidden and add strength to the joint.
• Dowel holes are drill and glued and clamped together.
• Dado's are typically used in making book shelves, they
support the shelf without the benefit of any additional
fasteners, any glue or hardware simply holds the shelf in
• Dados may be made with a dado blade on a table saw
47. Rabbet Joint
• This type of joint is made by using the dado blade.
• Each side of wood is cut to a specific length, then glued or
brad nailed to make a stronger joint.
48. Lap Joint
• A lap joint is when two pieces are cut on a dado & glued
or nailed together to create a stronger joint.
49. Dovetail Joints
• Most commonly used to attach drawer sides to drawer fronts, dovetails joints
almost always indicate quality furniture.
• Typically cut using a manufactured jig to cut these. Can be done by hand.
50. Mortise and Tenon
• The mortise and tenon joint is one of the strongest joints.
• Mortise and tenon joint is normally formed by cutting a
square tongue (the tenon) on the end of one piece of
wood and an equal size square hole or slot (the mortise)
51. Miter with Wood Spline
Mitered corners make the joint disappear. They have a clean look, and can be
strengthened with splines. Splines can be either hidden inside the joint or cut on
52. Tongue and Groove
• Tongue and groove is a method of fitting similar objects
together, edge to edge.
• T&G joints allow two flat pieces to be joined strongly
together to make a single flat surface.
• The effect of wood shrinkage is concealed when the joint is
beaded or otherwise molded.
54. WOOD AS A CONSTRUCTION MATERIAL:
Wood is a commonly used construction material in many parts of the world because
of its reasonable cost, ease of working, attractive appearance and adequate life if
protected from moisture and insects.
However, forests are a valuable natural resource that must be conserved, particularly
in areas with marginal rainfall. As good a material as wood may be, there are regions
where other materials should be considered first, simply on a conservation basis.
Wood for building is available from many different species
with widely varying characteristics. Some species are used
in the form of small poles for light construction, while other
species are allowed to mature so that timber may be sawn
from the large logs.
The species that produce small, inexpensive poles in rather
short growing periods often grow in the fringes of
agricultural land and can be used without danger to the
ecology of the region.
55. HISTORY OF WOOD IN CONSTRUCTION:
Wood has been an important construction material since humans began building
shelters, houses and boats. Nearly all boats were made out of wood until the late
19th century, and wood remains in common use today in boat construction.
A research team led by Willy Tegel and
Dr. Dietrich Hakelberg from the
Institute for Forest Growth of the
University of Freiburg, Germany has
succeeded in precisely dating four
water wells built by the first Central
European agricultural civilization.
The wells were excavated at
settlements in the Greater Leipzig
region and are the oldest known
timber constructions in the world.
They were built by the Linear Pottery
culture, which existed from roughly
5600 to 4900 BC.
56. Greensted Church, in the small
village of Greensted-juxta-Ongar,
near Chipping Ongar in Essex,
England, is the oldest wooden
church in the world, and
probably the oldest wooden
building in Europe still standing,
albeit only in part, since few
sections of its original wooden
Greensted Church has stood for
nearly 1,200 years.
Archaeological evidence suggests
that, before there was a
permanent structure, there may
well have been another church,
or a holy place, on the site for
much longer, possibly dating back
to around the 4th century.
57. HARDWOOD & SOFTWOOD:
Wood cut from deciduous trees is considered to be hardwood, while that cut from
coniferous trees is considered to be softwood. However, this classification does not
accurately reflect whether the wood itself is soft or hard. For example, balsa wood is
one of the lightest, least dense woods there is, and it's considered a hardwood.
60. CHARACTERISTICS OF WOOD:
Strength in wood is its ability to resist breaking when it
is used in beams and columns. Not only is strength
related to the species, but also to moisture content
(MC) and defects. Strength is also quite closely related
Hardness is the resistance to denting and wear. While
hardwoods are more difficult to work, they are required
for tools, tool handles, flooring and other applications
subject to wear, or where a high polish is desired.
61. Woods that are stiff resist deflection or bending when loaded. Stiff woods are not
necessarily very strong. They may resist bending up to a point and then break
Tough woods will deflect considerably before breaking. Even after fracturing, the
fibres tend to hang together and resist separation. Tough woods are resistant to
62. Warping is a deviation from flatness
as a result of stresses and shrinkage
from the uneven drying of lumber.
The types of wood warping include:
cup: a warp across the width of the
face, in which the edges are higher
or lower than the centre of the wood
bow: a warp along the length of the
face of the wood
twist: a distortion in which the two
ends do not lie on the same plane
crook: a warp along the length of the
edge of the wood
kink: a localized crook, often due to a
63. Nail-holding resistance for
hardwoods is greater than
for softer woods. However,
woods that are so hard that
they tend to split when
nailed, lose much of their
holding ability. Pre-boring
to 75 % of the nail size
The workability differs in hardwoods and
Sawing, shaping and nailing, is better for soft,
low-density woods than for hardwoods, but
usually they cannot be given a high polish.
64. SAWING TIMBER:
The method of sawing has a considerable effect on the appearance, resistance to
warping, shrinking, paint-holding ability and wear resistance of the final piece.
There are several methods of sawing a log into boards and planks, giving different
relationships between the growth rings and the surface, i.e. more or less parallel to
the surface in plain sawn timber and at right angles in radial sawn timber.
Radially sawn boards shrink less, are less liable to cup, twist & are easier to season.
Unfortunately cutting methods that produce a high proportion of quarter-sawn
timber are wasteful and hence used to produce material for high-class joinery work.
PLAIN-SAWN QUARTER-SAWN THROUGH & THROUGH CUT
65. SEASONING OF TIMBER:
The strength, stiffness and dimensional stability
of wood are related to its moisture content.
Hence, if wood is dried (seasoned) before use,
not only can higher strength values be used in a
design, but a more durable structure will result.
In developing countries, most timber is not
seasoned and it is sold in what is called its g ee
Timber must be stacked, supported and
sometimes restrained so as to minimize distortion
during seasoning. If drying is too rapid, the outer
parts, in particular the unprotected ends, shrink
before the interior does, and this leads to surface
checking and splitting, as well as the possible
extension of ring and heart shakes. Some timber
species are more difficult to season satisfactorily
66. GRADES OF TIMBER: EXAMPLE – TEAK WOOD
Teak grade is a common way of determining teak ood s quality and therefore
pricing. Teak furniture usually indicates the grade of the wood used to make it. The
grades that teak wood may have are A, B or C where A has the highest quality and
price while C is the lowest quality and pricing.
Teak wood graded A is wood is
taken from the heart of the trunk
where teak oil is more
concentrated. Also A grade teak has
more silica and rubber making it
more resistant to water and insects.
This means that the ood s texture
is more uniform and resistant. A
grade teak wood is about ten times
more expensive than than C or B
grade teak. Less than 20 percent of
a teak tree is considered A grade
67. Teak wood graded B is also great. Its quality is not as high as A
grade teak but its still fine for furniture. B grade teak wood is
taken from the outer part of the heart of the tree. It still has a
good concentration of natural oil. The color is a bit lighter than
the one you find in A grade teak wood. The touch is not as
smooth and is less shiny than A grade.
C grade teak is taken from the outer part of the teak log. It is
the lowest quality teak that you will find, also the cheaper.
Many cheap teak furniture is made from this type of wood.
Knots and flaws are common. The grain is not so tight making
this grade of teak a bit less resistant than B and A grade teak. C
grade teak is still a great wood. It is waterproof and very
resistant to insects but the overall wood quality is a bit lower.
94. SEASONING OF TIMBER:
As fresh timber which is obtained from trees contains about 30 to 40 % sap
or moisture. This sap is very harmful for the life of a timber. Therefore, it is
necessary to remove that sap by applying some special methods. All those
methods which are used timber. for removing the sap from timber are
collectively termed as seasoning of timber.
Advantages of seasoned timber:
It has reduced weight,
It is strong and durable,
It has resistance to decay or rot,
It takes high polish,
It is easier to work,
Its life is more.
95. (a) Kiln Seasoning:
In kiln seasoning timber is placed in a chamber with
some special heating arrangement.
In this process one thing should be kept in mind that
heating system should be under control, other wise
timber will be crack or wrap. The time required for
this seasoning is 3 to 12 days. This is quick process.
(b) Chemical Seasoning:
In chemical seasoning carbon dioxide, ammonium
carbonate or urea are used as agents for seasoning,
those are applied in dry state, the inter surface of
timber dries first than outer side.
This ensures uniform seasoning. The time required for
this seasoning is 30 to 40 days.
(c) Electric Seasoning:
In this method electric current is passed through the
timber logs. The time required for this seasoning is 05
to 08 hours.
96. (1) NATURAL SEASONING:
In the air seasoning or natural seasoning or natural drying, seasoning of timber, timber
is dried by direct action of air, wind and sun. In this method, the timber logs are
arranged one over the other, keeping some space or distance between them for air
circulation of fresh air.
Generally this type of seasoning requires few months to over a year, this is very slow
(2) ARTIFICIAL SEASONING
(a) Kiln Seasoning,
(b) Chemical Seasoning,
(c) Electric Seasoning
(3) WATER SEASONING:
In water seasoning, timber logs are kept immersed whole in the flowing water. The sap
present in timber is washed away. After that logs are taken out from water and are
kept in open air, so water present in timber would be dried by air. The time required
for this type of seasoning is 2 to 4 weeks.
97. DETERIORATION OF TIMBER (OR) DECAY OF TIMBER:
There are so many agencies which may cause decay of timber. But there are three main
harmful agencies which cause timber decay.
(1) Decay or Rot:
Decay or rot of timber is the result of the activity of various bacteria and fungi, which
utilize various portions of timber as food; they require both oxygen and excess
moisture. Hence timber having moisture content below 25 % will not rot easily.
There are so many insects which attack the wood, out of them termites (white ants) are
the main insects which are very dangerous for timber. Termites of one class live under
ground and eat wood and forms tubes or tunnels inside it.
Fire is also the damaging factor for timber. As timber has tendency to burn, so
fire can damage it easily.
98. PRESERVATION OF TIMBER
There are three main classes of timber preservatives.
(1) Oily substances insoluble in water
(2) Water soluble salts
Oily substances insoluble
Coal tar oil is the best known and widely used preservative material of this class. It is
obtained during the destructive distillation of bituminous coal. It is available in many
grades and types. It has high degree of penetration. It has highly toxic effect to wood
(2) Water soluble salts:
Zinc chloride is the most extensively used preservative of this type. It is clean and
99. SPECIAL PAINTS TO SAVE TIMBER
Following paints are used to save
timber from fire.
Mono ammonium phosphate,
Mono magnesium phosphate,
METHODS OF APPLYING PRESERVATIVES:
Before applying preservatives, the timber should be completely seasoned.
There are some important methods of applying timber preservatives which are given
Painting and dipping method
Pressure process or full cell process
Empty cell process
100. (1) Painting and dipping method:
This is the most common method in which the preservative material is applied by
means of a brush several times. The timber is also immersed in a tank full of liquid
p ese ati e ate ial . I oth t pes the pe et atio ha dl e eeds 1/1 . The
duration of immersion and temperature of solution is increased the penetration
(2) Pressure process or full cell process:
In this process, the timber is placed in an air tight chamber, from which air is with
drawn by creating a vacuum. The cells are full emptied to receive preservative
material. After that preservative material is pumped under pressure of 100 to 200
psi and at a temperature of 120degreeF. As the timber contains required quantity of
preservative a low vacuum is maintained to remove excess preservative. Such a
timber is generally used in case of piles in salt water and railway sleepers.
(3) Empty cell process:
This method is similar to the full cell process but initial vacuum is not to
be maintained and no attempt is to be made to remove the air from cells. The
preservative material is applied under pressure of 200 psi.
143. • Ancient Chinese wooden architecture is among the least studied of any of the world's great
architectural traditions from the western point of view.
• Although Chinese architectural history reaches far back in time, descriptions of Chinese
architecture are often confined to the well known Forbidden with little else explored by the
• Although common features of Chinese architecture have been unified into a vocabulary
illustrating uniquely Chinese forms and methods, until recently data has not been available.
• Because of the lack of knowledge of the roots of Chinese architecture, description of its
elements is often translated into Western terms and architectural theory, losing its unique
Ancient Chinese wooden architecture
• By the middle Neolithic period, the use of rammed earth and unbaked mud bricks was
• Hangtu, the pounding of layers of earth to make walls, altars, and foundations remained an
element of Chinese construction for the next several millennia.
• The Great wall of china, built of Hangtu, was erected beginning in the first millennium BC
• Sundried mud bricks and rammed mud walls were typically constructed within wood frames.
• Hard pounded earth floors were strengthened by heating.
144. • A fundamental achievement of Chinese wooden architecture is the load-bearing timber frame, a network of
interlocking wooden supports forming the skeleton of the building.
• This is considered China's major contribution to worldwide architectural technology. However, it is not known
how the builders got the huge wooden support columns into position.
• Unlike western architecture, in ancient Chinese wooden architecture, the wall only defined an enclosure, and
did not form a load-bearing element.
• Buildings in China have been supported by wooden frames for as long as seven millennia. The emergence of
the characteristics articulated wooden Chinese frame emerged during the Neolithic period.
• Seven thousand years ago mortise and tenon joinery was used to build wood-framed houses. (The oldest are
at Hemudu site at Zhejiang).
• Over a thousand of these sites have been identified, usually with circular, square or oblong shaped buildings.
During the Yangshao culture in the middle neolithic, circular and rectangular semi subterranean structures are
found with wooden beams and columns.
• Wooden beams or earth supported the roofs which were most likely thatched.
• As the villages and towns grew they adhered to symmetrical shapes. Symmetry was also important in the
layout of homes, altars, and villages.
• In traditional Chinese architecture, every facet of a building was decorated using various materials and
techniques. Simple ceiling ornamentations in ordinary buildings were made of wooden strips and covered
• More decorative was the lattice ceiling, constructed of woven wooden strips or sorghum stems fastened to the
• Dougong is a unique structural element of interlocking wooden brackets, one of the most important elements in
traditional Chinese architecture.
• It first appeared in buildings of the last centuries BC and evolved into a structural network that joined pillars and
columns to the frame of the roof. Dougong was widely used in the Spring and Autumn Period (770–476 BC)
and developed into a complex set of interlocking parts by its peak in the Tang and Song periods. Since ancient
times when the Chinese first began to use wood for building, joinery has been a major focus and craftsmen cut
the wooden pieces to fit so perfectly that no glue or fasteners were necessary
145. In traditional Chinese architecture, every facet of a building was decorated using various materials and
techniques. Simple ceiling ornamentations in ordinary buildings were made of wooden strips and covered with
paper. More decorative was the lattice ceiling, constructed of woven wooden strips or sorghum stems fastened
to the beams. Because of the intricacy of its ornamentation, elaborate cupolas were reserved for the ceilings of
the most important structures such as tombs and altars, although it is not clear what the spiritual beliefs of the
early Chinese were, as altars appear to have served as burial sites. In traditional Chinese architecture, the
layered pieces of the ceiling are held together by interlocking bracket sets (斗拱 dǒugǒng).
Elaborate wooden coffers (藻井 zǎojǐng) bordered by a round, square, or polygon frame with its brackets
projecting inward and upward from its base were used around the 7th century. Deeply recessed panels shaped
like a well (square at the base with a rounded top) were fitted into the ceiling's wooden framework. The center
panel of the ceiling was decorated with water lilies or other water plants. The relationship of the name to water
has been linked to an ancient fear that wooden buildings would be destroyed by fire and that water from
the zǎojǐng would prevent or quell the fire's flames.
The tomb of Empress Dowager Wenming of the Northern Wei Dynasty has a coffer in the flat-topped, vaulted
ceiling in the back chamber of her tomb. The Baoguo Temple in Yuyao in Zhejiang has three cupolas in the
ceiling, making it unique among surviving examples of Song architecture.
Sanqing Hall (Hall of the Three Purities) is the only Yuan period structure with three cupolas in its ceiling
Roof and ceiling
146. Bandon Bluff House
A modern house on the Oregon coast provides expansive views of the Pacific to the west and a river to the north.
Wood , concrete and rich colors make this house warm and comfortable year-round.
The expansive deck and outdoor fireplace
make this outdoor space useable year-round
the entry is protected from the strong coastal
The granite water feature connects
with the entry court pond.
147. The expansive deck and outdoor fireplace make this
outdoor space useable year-round
the entry is protected
from the strong coastal
The granite water feature
with the entry court
148. Yusuhara Wooden Bridge Museum
Architects: Kengo Kuma & Associates
Location: 3799-3 Taro-gawa Yusuhara-cho, Takaoka-gun,
Kochi Prefecture, Japan
Client: Tomio Yano, Town Mayor of Yusuhara
Site area: 14,736.47 sqm
Photographs: Takumi Ota Photography
• This is a plan to link two public buildings with a
bridge-typed facility, which had been long separated
by the road in between.
• The museum technically bridges communications in
this area. It functions not only as a passage
between the two facilities but also as an
accommodation and workshop, ideal location for
• In this project, we challenged a structural system
which composes of small parts, referring to
cantilever structure often employed in traditional
architecture in Japan and China.
• It is a great example of sustainable design, as you
can achieve a big cantilever even without large-
• ‘Dendro-’ from the
Greek word meaning tree
• ‘-ology’ meaning the
• Dendrology is the
study of trees and includes
ranges, morphology, and
• Taxonomy is the study of the
classification of living things.
• Morphology is the study of the shape,
general appearance, or form of an
• Silviculture is the care and cultivation
of forest trees.
• Ecology is the study of the relationships
between living and non-living things and