DEFECTS OF TIMBER

DEFECTS OF TIMBER:

                                           Any disturbance in the quality that affects the strength, workability, durability, utility, appearance and decay etc is said to be the defects in timber.

Growth Related Defects:

1. Shakes:

  Change in shape of trunk or cracks in timber are called shakes. It is of three types.

·         Star shakes.

·         Hearth shakes.

·         Cap.

2. Knots:

                  A knot is the base of branch that is attached with the wood of tree trunk or to a large branch.

3. Rind galls:

                    Swelling due to injuries inflected to the wood in its younger age.

4.     Twisted fibers:

                      Wood is twisted due to strong winds during the early stages of its growth.

5.     Upsets:

                  Change in wood direction in young age by to fast blowing winds.

DEFECTS AFTER FELLING:

1. Wane:

                 The roundness of timber surface without bark.

2. Twists:

                Ends of the trunk are twisted in opposite directions.

3. Bow:

                Curve made along the face of timber due to shrinkage.

4. Cupping:

                     Curve formed across the width of trunk.

5. Checks: -

During felling of tree from stem internal stresses causes checks.

6. Splits:

Splits are the lengthwise separation occurs due to the reason of inappropriate handling of drawing stresses or forces.

Types of Timber

Types of Timber:

                       According to its botanical origin wood is classified into two kinds:

Soft wood:

                 Soft wood is obtained from Gymnosperms. Soft wood from coniferous trees like pine etc, , and are generally lighter and  simple in structure.

Hard wood:

                 Hard wood is produced from Angynosperm, known as Dicotyledons. They contain broad leaf trees and are strong, harder and more complex.

CHARACTERISTICS OF SOFT WOOD:

·         Light in color

·         Fast or rapid  growth

·         Low weight

·         Low density

·         Distinct annual rings

·         Hearth wood and Sap wood cannot be separated or distinguished

·         Strength is strong along the grains

·         Conversion is easy

·         Resonance material usually exist in pores

 Examples are chirr, fir and other conifers.

CHARACTERISTICS OF HARDWOOD:

·          Dark in color

·         Slow or gradual  growth

·         Heavier weight

·         High density

·         Indistinct annual rings

·         Hearth wood and Sap wood can be separated or distinguished

·         Strength is strong along and across the grains

·         Conversion is difficult

Examples are sheshum, oak, teak and other desidous trees.

Timber and Parts of Timber

TIMBER:

It is defined as:

      “TIMBER IS THE MATERIAL OR PRODUCT OBTAINED WHEN CUT AND MACHINED FROM THE TREES”

PARTS OF Timber:

 Generally there are three parts of a tree i.e.;

1.      Roots

2.      Stem

3.      Branches

PARTS OF TRUNK:

Trunk is said to be the main woody stem of a Tree.

Trunk parts are:

1. Bark:

      The protected outside cover of the trunk located outside is called bark.

2. Annual Rings:

                         These are also called the growth rings of the tree. These are actually the marks or positions show the yearly growth of the trunk.

3. Pith:

            The central or inner part of the trunk.

4. Hearth Wood:

              The wood which is responsible for surrounding the pore of the trunk.  Usually dark in color and have little or no sap.

5. Sap Wood:

                Most recent annual rings formed in this portion of the trunk. It is about 20-50% of the total radius of trunk.

6. Cambium Layer:

                         Development or growth area of the trunk is called cambium layer.

7. Xylem:

            Transportation of water is done through this part of wood/trunk.

8. Phyleum:

                   The inner part of the bark responsible for the transports organic nutrients to the wood, in case of trees it is Sucrose.

Timber and Parts of Timber