Forest soils store 50% less carbon than grassland - scientists warn of over-reliance

Researchers studied carbon in soil (University of Stirling/PA) PA Media

Forests may be less effective at fighting climate change than previously thought, according to new research that challenges their role as a primary solution to global warming. Scientists from the University of Stirling found that deep forest soils store significantly less carbon long-term than assumed, potentially undermining tree-planting campaigns worldwide.

A study of 16 pine plantation sites in the Scottish Lowlands revealed a striking finding: soils under mature pine forests – some planted 68 years ago – contained only about half as much carbon as nearby grassland soils. The carbon loss equals roughly one-third of all carbon that the trees absorbed from the atmosphere through photosynthesis.

Professor Jens-Arne Subke, who co-authored a new commentary on the findings in Global Change Biology, warned of the implications. «Our findings emphasised that we cannot over-rely on forests to mitigate the impacts of climate change because there is still so much that we don't understand,» he said. «Despite accumulating tree biomass, we may be losing carbon capital – the carbon stored long term in soils and ecosystems – to the atmosphere.»

The research team also found that carbon stored in forest soils was less stable than expected, indicating higher potential for breakdown and future release into the atmosphere. Ignoring these deep soil carbon dynamics could lead to over-optimistic estimates of forests' climate benefits, the scientists cautioned.

Dr Thomas Parker from the James Hutton Institute emphasized the need for realistic expectations. «Forests are an essential for human and planetary well-being for a range of reasons, but we need to acknowledge that they are not a silver bullet for all our problems,» he said. «There are complexities and trade-offs that need to be understood to maximise the net benefits that we gain from forests.»

The research, which examined European beech forests in Central Europe alongside Scottish pine plantations, was funded by the National Environmental Research Council and the National Science Foundation. The findings were published in the Journal of Environmental Management.

Note: This article was created with Artificial Intelligence (AI).