Processing of Wood: From Trees 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 years

Topic: Processing of Wood
Sub-topic: Stages of Wood Processing and Parts of a Tree

Duration: 40 minutes

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

1. Define timber and identify its source.
2. List the stages of processing wood.
3. Identify the parts of a tree and explain their functions.
4. Describe the process of photosynthesis.

Keywords: Timber, Wood Processing, Photosynthesis, Conversion, Seasoning

Set Induction:
Ask the students if they have seen a carpenter working on wood and what they think wood is used for. Lead the discussion into how wood is processed from trees.

Entry Behaviour:
Students are familiar with trees and can identify wood as part of their environment.

Learning Resources and Materials:
Pictures of trees, wood processing stages, and wood products. Samples of softwood and hardwood.

Building Background/Connection to Prior Knowledge:
Students already have basic knowledge of trees and plants from previous lessons in Agricultural Science.

Embedded Core Skills:

• Critical thinking
• Observation
• Problem-solving

Learning Materials:
Lagos State Scheme of Work, textbooks, and wood samples.

Reference Book:
Lagos State Basic Technology Scheme of Work

Instructional Materials:

• Pictures of various trees
• Samples of processed wood (softwood and hardwood)
• Charts showing the parts of a tree

Content

Processing of Wood
Wood is processed from trees. The technical name for wood is timber. Timber is obtained from the trunk of a mature tree. It is used for making furniture and for construction. The stages involved in processing wood are:

1. Tree Growth:
   Trees are grown in natural forests or plantations.
   • Natural forests can be found in tropical rainforests, such as those in the South-West of Nigeria.
   • Plantations: Tree seedlings are planted, and softwoods take about 10 years to mature, while hardwoods can take between 40 to 100 years.
2. Felling:
   The trees are cut down using chainsaws or other tools.
3. Conversion:
   The tree trunk is cut into logs for easy transportation and further processing.
4. Seasoning:
   The wood is dried to remove moisture. This process can be done naturally (air-drying) or artificially (kiln-drying).
5. Preservation:
   The wood is treated to prevent decay, insect attacks, and damage from moisture.

Parts of a Tree

1. Root:
   The root holds the tree in the ground and draws water and minerals from the soil.
2. Leaves:
   The leaves are responsible for photosynthesis.
   • Photosynthesis is the process by which green plants manufacture food using carbon dioxide (CO₂), water, and sunlight. The part of the leaf responsible for this is the chlorophyll.
3. Bark:
   The bark protects the tree from external attacks by pests and diseases.
4. Stem/Trunk:
   The trunk provides support and contains the wood (timber) that is used for construction and furniture.

Evaluation Questions:

1. Timber is obtained from the __________ of a tree.
   a) Root
   b) Trunk
   c) Leaves
   d) Bark
2. The process of cutting down a tree is called __________.
   a) Conversion
   b) Felling
   c) Preservation
   d) Seasoning
3. Softwoods take about __________ years to mature.
   a) 10
   b) 20
   c) 40
   d) 100
4. Photosynthesis occurs in the __________ of the leaf.
   a) Root
   b) Chlorophyll
   c) Bark
   d) Trunk
5. The process of drying wood to remove moisture is called __________.
   a) Conversion
   b) Felling
   c) Seasoning
   d) Preservation
6. The root of a tree is responsible for __________.
   a) Photosynthesis
   b) Water absorption
   c) Supporting leaves
   d) Protecting the trunk

Class Activity Discussion

1. What is timber?
   Timber is the processed wood obtained from the trunk of a tree.
2. What are the stages of processing wood?
   The stages are tree growth, felling, conversion, seasoning, and preservation.
3. Where is timber obtained from?
   Timber is obtained from the trunk of a mature tree.
4. What is photosynthesis?
   Photosynthesis is the process by which green plants use sunlight to produce food.
5. What are softwood and hardwood?
   Softwood trees grow faster and take about 10 years to mature, while hardwood trees take longer (40-100 years) to mature.

Presentation

Step 1:
Review the previous lesson on trees and plants. Discuss how trees are important in our environment.

Step 2:
Introduce the topic of wood processing. Explain how wood is processed starting from the tree growth stage to the final preservation.

Step 3:
Allow the students to contribute by naming trees around their area. Show them pictures of different types of trees, and explain the functions of each part.

Teacher’s Activities:

• Show pictures of trees and explain the different stages of wood processing.
• Demonstrate the difference between hardwood and softwood.

Learners’ Activities:

• Observe the pictures and samples provided.
• Participate in class discussions by naming trees they are familiar with.
• Answer questions on the parts of a tree and wood processing.

Assessment:

1. What is the technical name for wood?
2. List the stages involved in wood processing.
3. Describe the function of the roots of a tree.
4. What is photosynthesis?
5. How long does it take for softwood to mature?

Evaluation:

1. What is timber used for?
2. Name the process by which wood is dried.
3. Explain the role of the leaves in a tree.
4. How is hardwood different from softwood?
5. What part of the tree holds it in the ground?

Conclusion:
The teacher will move around the class, ensuring the students’ understanding of the lesson content and correcting any misconceptions where necessary.