Unit 4
¹ Fires are often started deliberately. Some landowners set fire to trees in order to clear land to plant crops. Hunters and loggers start fires to clear paths through the forest. ² Many forest fires are started accidentally. People burn garbage or use machines and sparks fly into the dry bush. Careless visitors drop cigarette ends. Others have barbecues and don’t put them out properly. Often they start fires without knowing that they have done so. ³ Finally, and most worryingly, there are some people, including children, who start fires for fun. Forest fires lead to floods 4 Forest fires happen in the dry season but fire affects the environment for a long time afterwards. 5 In a forest, the trees form a strong network of roots that keep the soil in
Cause and effect
place. When the trees have gone, the soil is loose and is washed away by rain. When it rains again, the water cannot soak into the soil so it runs off and causes flooding.
Rain can’t soak away and causes flooding.
Rain washes soil away.
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Rain soaks into soil.
AFTER the fire
BEFORE the fire
Can forests recover? Forests can recover but it takes many, many years. The average age of a forest tree is about 70–100 years and trees in some forests can be many hundreds of years old!
Glossary environment the world around us oxygen one of the gases in air raw materials basic material from which other things are made, such as wood or iron
A glossary is a list of unusual words used in a passage.
• Ask students what they think a logger is (paragraph 1). Ask them to guess from the context and from the word ‘log’ within the word. • Remind students to use context clues . They should read on a little way and also re-read the previous sentence to help them guess the meaning. • Paragraphs 1, 2 and 3 can be used to identify the main idea/topic sentence and details.
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