Savanna grasses beat trees in battle against climate change, according to a UCT study.
Planting trees in African savannas may undermine biodiversity without delivering the expected gains in carbon storage, a groundbreaking new study has revealed. The research, led by the University of Cape Town (UCT) and Conservation South Africa, discovered that open grasslands are highly efficient carbon sinks, with grasses—not trees—responsible for more than 90 per cent of the carbon locked away in sandy savanna soils.
Published in the journal Functional Ecology, the findings challenge the widely held global assumption that increasing tree cover is an infallible weapon against climate change, warning that well-intentioned tree-planting initiatives could do more environmental harm than good.
Using specialised open-top growth chambers to simulate future environmental shifts, researchers grew five species of savanna trees alongside the grass species Themeda triandra under both current and elevated atmospheric carbon dioxide levels. Because trees use a photosynthetic pathway that is typically less efficient at capturing carbon dioxide than that of grasses, scientists initially expected rising emissions to give trees a competitive advantage.
