HomeJSS 3BASIC TECHNOLOGYThe Step-by-Step Process of Wood from Tree to Timber

The Step-by-Step Process of Wood from Tree to Timber

Basic Technology JSS 3 First Term Lesson Notes Week 1

Subject: Basic Technology

Class: JSS 3
Term: First Term
Week: 1
Age: 13–14 years
Topic: Processing of Materials – Wood
Sub-topic: Wood Felling, Conversion, Seasoning, and Defects

Duration: 40 minutes

Behavioral Objectives:

By the end of the lesson, students should be able to:

  1. Explain the process of wood felling.
  2. Describe the methods of wood conversion.
  3. State the importance of wood seasoning.
  4. Identify common wood defects and their causes.

Keywords:

  • Wood Felling
  • Conversion
  • Seasoning
  • Defects

Set Induction:

The teacher shows students a piece of raw wood and a polished wooden furniture piece, asking them to observe the difference. The teacher then explains how wood is processed from its raw state to its finished form.

Entry Behaviour:

Students are familiar with wood as a material used for making furniture, doors, and windows.

Learning Resources and Materials:

  • Pictures of trees, logs, and wooden products.
  • Samples of raw and seasoned wood.
  • Models showing different defects in wood.

Building Background/Connection to Prior Knowledge:

Students have seen and used wooden materials in their homes, such as chairs, tables, and doors. They understand that wood comes from trees, but the processing stages are unfamiliar to them.

Embedded Core Skills:

  • Critical thinking
  • Observation
  • Analytical skills

Reference Book:

  • Lagos State Scheme of Work for Basic Technology JSS 3

Instructional Materials:

  • Wood samples
  • Charts showing stages of wood processing
  • Examples of defective wood

Content:

Stages in the Processing of Wood

  1. Wood Felling:
    • Wood felling refers to the process of cutting down trees. It is usually done when the tree has matured and is ready for use. The process involves selecting mature trees in a forest or plantation and cutting them using chainsaws or manual tools.
  2. Conversion:
    • Conversion refers to cutting the felled tree into useful sizes such as planks, beams, and boards. There are two main types of conversion methods:
      • Through and Through Conversion: The log is cut along its entire length into planks.
      • Quarter Sawn Conversion: The log is cut into quarters before being cut into planks. This method reduces the chances of warping and splitting.
  3. Seasoning:
    • Seasoning is the process of drying wood to reduce its moisture content. This makes the wood more durable and stable for use. There are two main types of seasoning:
      • Natural Seasoning: Wood is left to dry in the open air over time.
      • Kiln Seasoning: Wood is dried in a controlled environment using heat.
  4. Defects in Wood:
    • Defects are flaws in wood that reduce its quality. Some common wood defects include:
      • Knots: Formed where branches were attached to the tree.
      • Warping: The wood bends due to uneven drying.
      • Cracks/Splits: Caused by excessive moisture loss.
      • Insect Damage: Wood is eaten or damaged by insects like termites.

Processing of Wood

Technical Name:
The technical term for wood used in construction is timber.

Timber is obtained from the trunk of a mature tree, and it is used to produce quality products such as furniture and in building construction.

Stages of Processing Wood

  1. Tree Growth:
    • Trees grow in natural environments such as tropical rainforests, commonly found in the southwestern part of Nigeria, or in plantations.
  2. Felling:
    • This is the process of cutting down mature trees that are ready for processing.
  3. Conversion:
    • The felled trees are then cut into useful shapes and sizes, such as planks and beams.
  4. Seasoning:
    • This is the drying process, which removes moisture from the timber to prevent warping and increase durability.
  5. Preservation:
    • Timber is treated with chemicals to protect it from insects, fungi, and other elements that can cause decay.

 

Questions with Options:

  1. The process of cutting down trees is known as __________.
    a) Felling
    b) Conversion
    c) Seasoning
    d) Defects
  2. The first stage in wood processing is __________.
    a) Seasoning
    b) Felling
    c) Conversion
    d) Defects
  3. A common method for drying wood is called __________.
    a) Knots
    b) Warping
    c) Seasoning
    d) Conversion
  4. __________ is used to protect wood from insect damage.
    a) Kiln
    b) Preservative
    c) Conversion
    d) Defects
  5. A log that is cut into quarters before planking is known as __________.
    a) Through and Through
    b) Quarter Sawn
    c) Defects
    d) Knots
  6. A common defect caused by insect attack is __________.
    a) Knot
    b) Warping
    c) Insect Damage
    d) Cracking
  7. __________ is a method of drying wood using heat.
    a) Kiln Seasoning
    b) Air Drying
    c) Quarter Sawn
    d) Through and Through
  8. Warping occurs when wood is __________.
    a) Kiln dried
    b) Air dried
    c) Unevenly dried
    d) Cracked
  9. Cracks in wood are often caused by __________.
    a) Excessive moisture
    b) Knots
    c) Preservatives
    d) Defects
  10. The presence of __________ indicates where a branch was attached to the tree.
    a) Crack
    b) Knot
    c) Warping
    d) Split
  11. Wood that bends due to uneven drying is called __________.
    a) Warped
    b) Cracked
    c) Split
    d) Knotted
  12. Natural seasoning of wood is done by __________.
    a) Air drying
    b) Kiln drying
    c) Conversion
    d) Felling
  13. Wood is cut into useful sizes during the process of __________.
    a) Felling
    b) Conversion
    c) Seasoning
    d) Preservation
  14. The drying of wood to remove moisture content is called __________.
    a) Felling
    b) Conversion
    c) Seasoning
    d) Warping
  15. __________ is the method used to control moisture loss in wood.
    a) Conversion
    b) Felling
    c) Seasoning
    d) Defects

15 Frequently Asked Questions (FAQs) with Answers:

  1. What is wood felling?
    • Wood felling is the process of cutting down mature trees for processing.
  2. What happens during wood conversion?
    • Wood conversion involves cutting the felled tree into useful sizes like planks and beams.
  3. Why is wood seasoning important?
    • Seasoning reduces the moisture content in wood, making it more durable and resistant to warping.
  4. What are the types of seasoning?
    • The two types are natural seasoning (air drying) and kiln seasoning (heat drying).
  5. What is a common defect in wood?
    • Knots, which form where branches were attached, are a common defect.
  6. How does warping occur in wood?
    • Warping occurs when wood dries unevenly, causing it to bend.
  7. What is kiln seasoning?
    • Kiln seasoning is a process where wood is dried in a controlled environment using heat.
  8. What is natural seasoning?
    • Natural seasoning is drying wood in the open air over a period of time.
  9. What are knots in wood?
    • Knots are marks in wood that show where branches were once attached to the tree.
  10. How can insects damage wood?
    • Insects like termites can eat into the wood, causing damage and weakening it.
  11. What is the function of preservatives in wood?
    • Preservatives protect wood from decay and insect damage.
  12. What is quarter sawn wood?
    • Quarter sawn wood is cut into quarters before being sawn into planks to reduce warping.
  13. What is through and through conversion?
    • Through and through conversion is when wood is cut along its entire length into planks.
  14. Why do cracks appear in wood?
    • Cracks often appear when wood loses too much moisture too quickly.
  15. What causes wood defects?
    • Defects are caused by factors like uneven drying, insect damage, and natural tree growth patterns.

Presentation (Steps 1–3):

Step 1: The teacher revises the previous lesson on types of materials.
Step 2: The teacher introduces the topic of wood processing, describing each stage.
Step 3: The teacher allows students to observe wood samples and ask questions about the defects, felling, and seasoning process.

Teacher’s Activities:

  • Explain each stage of wood processing.
  • Show pictures and samples of wood in different stages.
  • Encourage students to ask questions.

Learners’ Activities:

  • Observe wood samples.
  • Participate in the discussion on the importance of each stage of wood processing.
  • Answer questions based on the lesson.

Assessment:

  1. Define wood felling.
  2. List three types of wood defects.
  3. What is seasoning in wood processing?
  4. Explain quarter sawn conversion.
  5. How is kiln seasoning done?

Evaluation Questions:

  1. What is the purpose of wood conversion?
  2. Define seasoning in wood processing.
  3. List the defects commonly found in wood.
  4. What is the role of preservatives in wood treatment?
  5. Why is kiln seasoning faster than natural seasoning?
  6. Explain through and through conversion.
  7. What is warping in wood?
  8. Name two types of wood seasoning.
  9. How do insects damage wood?
  10. What is quarter sawn wood?

Conclusion:

The teacher goes around to check students’ notes and ensures they understand the stages of wood processing

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