Forest soils have an important role in protecting our climate: they remove large quantities of methane – a powerful greenhouse gas – from our atmosphere.
Forest soils have an important role in protecting our climate: they remove large quantities of methane – a powerful greenhouse gas – from our atmosphere. Researchers from the University of Göttingen and the Baden-Württemberg Forest Research Institute (FVA) evaluated the world's most comprehensive data set on methane uptake by forest soils. They discovered that under certain climate conditions, which may become more common in the future, their capacity to absorb methane actually increases. The data is based on regular measurements at 13 forest plots in south-western Germany over periods of up to 24 years. The study found forest soils absorb an average of three percent more methane per year. The researchers attribute this to the climate: declining rainfall leads to drier soils which methane penetrates more easily than moist soils. In addition, microorganisms break down methane more quickly as temperatures rise. The results were published in Agricultural and Forest Meteorology.
The researchers measured methane uptake by the soil. They measured soil gas profiles which reflect the chemical composition of the air in the soil at various depths. The data set comes from the FVA's soil gas monitoring programme. Over a period of many years, samples of air from the soil were taken every two weeks using thin tubes inserted into the earth and analysed in the laboratory. The researchers verified their calculations with independent measurements which involved placing an airtight measuring chamber on the soil surface. If the concentration of a gas such as methane decreases inside the chamber, it is possible to calculate whether and how much gas is being absorbed by the soil.
Read more at: University of Gottingen
The data on methane uptake comes from soils in beech and spruce forests, like the typical Central European beech forest shown here. (Photo Credit: Martin Maier)
