Afforestation, forest regeneration and peatland restorationSpec D4.3.8
In short
Afforestation, forest regeneration and restoration of peat-forming wetlands are approaches to carbon sequestration: removing carbon dioxide from the atmosphere and storing it as organic carbon. Scientists debate whether plantations of non-native trees or rewilding with native species is best. Peat forms in waterlogged soils, where decomposition is slow.
Carbon sequestration is the capture of carbon dioxide from the atmosphere and its long-term storage, here as organic carbon in plants and soil.
| Approach | What it involves |
|---|---|
| Afforestation | Planting trees on land that has not been forest for a long time |
| Forest regeneration | Allowing or helping forest to regrow on land where it has been cleared |
| Restoration of peat-forming wetlands | Blocking drains to rewet peatland, so waterlogged conditions return and peat forms again |
Peat forms because waterlogged soil is anaerobic and acidic, so decomposers break down dead plant matter very slowly and carbon accumulates. Peat formation naturally occurs in waterlogged soils in temperate and boreal zones, and also very rapidly in some tropical ecosystems.
| Approach | For | Against |
|---|---|---|
| Plantations of non-native trees | Fast-growing species can absorb CO₂ quickly | Often monocultures with low biodiversity; harvesting releases stored carbon |
| Rewilding with native species | Higher biodiversity; more resilient to pests and climate | May sequester carbon more slowly at first |
When asked to evaluate, weigh both sides: speed of carbon uptake against biodiversity and long-term storage.
Quick check
Which two greenhouse gases does the guide limit anthropogenic causes to?
Show answer
Carbon dioxide and methane.
What is legacy carbon?
Show answer
Old organic carbon in deep soil layers of boreal forest that survived earlier fires.
What causes coral bleaching?
Show answer
Increases in water temperature cause corals to expel their symbiotic algae.
Written and checked against the IB Biology SL specification · Updated October 2026