Explain how afforestation can help maintain the environment and support biodiversity.

OCR GCSE Biology A: Gateway Science (J247) — B6.1 Monitoring and maintaining the environment · Explain · 4 marks · View as Markdown

Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).

Large areas of forest in South America have been cleared for agriculture over many decades. Conservation organisations are now funding large-scale tree-planting programmes in these regions to restore the lost woodland.

Model answer (4 marks)

Afforestation creates new forest habitats, increasing the number and variety of habitats available.
This greater habitat diversity supports a larger number of species, thereby raising biodiversity.
Trees and plants absorb CO₂ during photosynthesis, reducing atmospheric greenhouse gases.
Lower greenhouse gas levels help stabilise the climate, protecting ecosystems and the organisms that depend on them.

Examiner tips

Use the exact terms from the mark scheme (habitat, biodiversity, CO₂, stabilise the climate).
Show the causal chain: more habitats → more species → higher biodiversity, and CO₂ absorption → climate stabilisation.

Common mistakes

Confusing afforestation with reforestation or not linking CO₂ absorption to climate change.
Using vague phrases like ‘good for the environment’ without specific mechanisms.

Mark scheme (4 marks)

Afforestation increases the number/variety of habitats available
A greater variety of habitats supports a greater variety of species / increases biodiversity
Trees/plants absorb carbon dioxide during photosynthesis, reducing greenhouse gas levels / helping to reduce climate change
Reducing climate change / stabilising the environment helps protect ecosystems and the organisms within them

Key terms in this question

afforestation · biodiversity