Class: Senior Secondary School 1 (SS1 / SSS 1)
Term: 2nd Term
Week: 1
Age: 15 years
Duration: 45 minutes
Subject: Furniture Making
Curriculum Theme: Trade
Previous Lesson: .
Topic: Timber Growth
Subject Matter: Parts of a tree, Types of tree growth, Tree growth process

Specific Objectives

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

Cognitive Domain:

Define timber growth.
Identify and name the different parts of a tree.
Describe the two main types of tree growth.
Explain the process by which trees grow.

Affective Domain:

Appreciate the importance of understanding tree structure for furniture making.
Show interest in learning about different aspects of tree growth.

Psychomotor Domain:

Sketch and accurately label the parts of a tree.
Differentiate between exogenous and endogenous tree growth using examples or diagrams.

Participate actively in class discussions on timber growth.
Collaborate with peers to identify and discuss tree characteristics.

Reference Materials

The following resources were used in planning this lesson:

9 Years Basic Education Curriculum for Technical Vocational Education.
State Unified Scheme of Work for Senior Secondary Schools.
Ojo, J. (2018). Furniture Making for Senior Secondary Schools, Book 1. Evans Brothers (Nigeria Publishers) Limited.
https://www.waeconline.org.ng/
https://www.nerdc.gov.ng/

Instructional Materials

The teacher will teach this lesson with the aid of:

A large chart showing a detailed diagram of a tree with its parts.
A sample wood log or cross-section of a tree trunk.
Whiteboard and markers.
Pictures of different types of trees (e.g., palm tree, iroko tree).

Rationale for the Lesson

This lesson is important because it helps pupils understand the basic structure and growth patterns of the primary raw material in furniture making: timber. Understanding how a tree grows and its different parts enables pupils to better appreciate the properties and characteristics of wood they will use.

Prerequisite/Previous Knowledge

Pupils are expected to have some basic knowledge about trees and their general functions from their Integrated Science lessons in Junior Secondary School.

Lesson Content/Board Summary

Timber Growth

Parts of a Tree

A tree is a perennial plant with an elongated stem, or trunk, supporting branches and leaves. Understanding its parts is essential for timber use.

The main parts of a tree include:

Roots: Anchor the tree and absorb water and nutrients from the soil.
Trunk/Stem: The main woody body of the tree, supporting the crown and transporting water and nutrients. It is the primary source of timber.
Branches: Woody extensions from the trunk that support the leaves.
Leaves: The primary organs for photosynthesis, where food is produced for the tree.
Crown: The upper part of the tree, consisting of branches and leaves.

Types of Tree Growth

Trees grow in different ways, which affects their structure and suitability as timber.

The two main types of tree growth are:

Exogenous Growth: These trees grow outwards by adding new layers of wood each year, forming annual rings. Most timber-producing trees (e.g., Iroko, Mahogany, Teak) belong to this group. Their stems are typically solid and cylindrical.
Endogenous Growth: These trees grow inwards from the centre, producing new cells internally. They do not form annual rings. Examples include palm trees, bamboo, and rattan. Their stems are often hollow or fibrous, and they are generally not used for solid timber construction in the same way as exogenous trees.

Tree Growth Process

Tree growth involves several biological processes that result in the formation of wood.

The key aspects of tree growth process are:

Photosynthesis: Leaves convert sunlight, water, and carbon dioxide into food (sugars) for the tree.
Cambium Layer: This is a thin layer of living cells located between the bark and the wood. It is responsible for the outward growth of the tree, producing new wood (xylem) towards the inside and new bark (phloem) towards the outside.
Annual Rings: In exogenous trees, the cambium produces distinct layers of wood each year, forming visible concentric rings. These rings can indicate the age of the tree and its growth conditions.
Sapwood: The outer, younger, and lighter-coloured wood layer that actively transports water and nutrients.
Heartwood: The inner, older, darker, and denser part of the wood that is no longer active in transport but provides structural support.
Bark: The outermost protective layer of the tree trunk and branches.

Teaching Methods/Instructional Techniques

Discussion, Lecture, Demonstration, Question and Answer, Visual Aids

Instructional Procedures

Step 1: Introduction

Time: 5 minutes
Teaching Skill: Set Induction
Teacher’s Activity: The teacher greets the pupils and asks them to name some things made from wood. The teacher then asks what wood is and where it comes from, leading them to the topic of trees and timber growth.
Pupils’ Activity: Pupils respond to the questions and share their ideas.
Learning Point: Pupils are engaged and the lesson topic is introduced.

Step 2: Presentation of Parts of a Tree

Time: 10 minutes
Teaching Skill: Explanation/Demonstration
Teacher’s Activity: The teacher displays the tree diagram chart and the sample wood log. The teacher points to and explains the different parts of a tree (roots, trunk, branches, leaves, crown, bark, sapwood, heartwood) using the visual aids.
Pupils’ Activity: Pupils observe the chart and log, listen attentively, and ask questions for clarification.
Learning Point: Pupils can identify and name the major parts of a tree.

Step 3: Explanation of Types of Tree Growth

Time: 10 minutes
Teaching Skill: Lecture/Illustration
Teacher’s Activity: The teacher explains the two main types of tree growth: exogenous and endogenous. The teacher uses the cross-section of the wood log to illustrate exogenous growth (annual rings) and uses pictures to show endogenous trees like palm or bamboo, highlighting the differences relevant to timber.
Pupils’ Activity: Pupils listen, observe the illustrations, and take notes, understanding the distinction between the two growth types.
Learning Point: Pupils understand the difference between exogenous and endogenous tree growth.

Step 4: Discussion on Tree Growth Process

Time: 10 minutes
Teaching Skill: Explanation/Questioning
Teacher’s Activity: The teacher explains the process of tree growth, focusing on the cambium layer, photosynthesis, and the formation of annual rings. The teacher asks questions to ensure understanding of terms like sapwood and heartwood.
Pupils’ Activity: Pupils participate in the discussion, answer questions, and consolidate their understanding of how trees grow.
Learning Point: Pupils grasp the fundamental processes involved in timber growth.

Step 5: Teacher’s Sketch/Demonstration

Time: 5 minutes
Teaching Skill: Modelling/Demonstration
Teacher’s Activity: The teacher sketches a simplified diagram of a tree on the whiteboard, clearly labeling its main parts as a model for pupils.
Pupils’ Activity: Pupils observe the teacher’s sketch and prepare their notebooks for their own drawing activity.
Learning Point: Pupils see a practical example of how to sketch and label tree parts.

Step 6: Pupils’ Activity

Time: 5 minutes
Teaching Skill: Practical Application
Teacher’s Activity: The teacher instructs pupils to sketch a tree in their notebooks and label its main parts based on what has been taught and demonstrated.
Pupils’ Activity: Pupils draw and label the parts of a tree in their notebooks.
Learning Point: Pupils apply their knowledge through a practical drawing task.

Step 7: Evaluation/Review

Time: 5 minutes

Teaching Skill: Questioning/Assessment

Teacher’s Activity: The teacher evaluates the learning by asking the following questions:

Define timber growth.
Mention any four parts of a tree.
State the two main types of tree growth.
Explain the role of the cambium layer in tree growth.

Pupils’ Activity: Pupils answer orally and in writing.

Learning Point: Pupils demonstrate understanding of the lesson.

Step 8: Conclusion

Time: 5 minutes
Teaching Skill: Summarization
Teacher’s Activity: The teacher summarizes the key learning points of the lesson, reiterating the importance of understanding tree growth for furniture making. The teacher assigns homework: research different local timber species and identify their growth characteristics.
Pupils’ Activity: Pupils listen to the summary and copy down the homework.
Learning Point: Pupils consolidate their learning and are given a task to reinforce knowledge.

Lesson Keywords

Timber – Wood prepared for use in building or carpentry.
Exogenous – Growing from the outside, adding layers annually (e.g., most trees).
Endogenous – Growing from within or from the centre (e.g., palms, bamboos).
Cambium – The thin layer of living tissue between the bark and wood, responsible for growth.
Sapwood – The outer, younger wood of a tree, actively transporting water.
Heartwood – The dense, innermost part of a tree trunk, usually darker and no longer active in transport.
Bark – The tough, protective outer sheath of the trunk and branches of a tree.
Annual Rings – Concentric layers of wood in a tree trunk, each representing one year’s growth.

Differentiation

For visual learners, the detailed tree diagram chart and wood log sample will be particularly helpful. Kinesthetic learners will benefit from sketching the tree parts. Struggling learners can be paired with stronger peers for the drawing activity and receive additional guidance from the teacher. Advanced learners can be encouraged to research specific local timber species and their growth cycles as an extension activity.

Note for teachers using this lesson plan

Teachers should ensure that the visual aids (tree diagram and wood log) are clear and large enough for all pupils to see. Encourage active participation and questions to gauge understanding. Emphasize the practical relevance of understanding timber growth to the study of furniture making, linking it to the properties and selection of wood. If possible, bring in samples of different wood types to show variations in grain and colour related to growth.