Greenhouse Gas Dynamics in Forest Soils

This research area mainly concerns the strong greenhouse gases methane and nitrous oxide. These gases are found only in trace amounts in the atmosphere, yet they still contribute significantly to the greenhouse effect.

Our main topic is how forest management and forest change alter the dynamics of methane and nitrous oxide. Forest management is in some areas currently moving in the direction of less intensive management, e.g. close-to-nature management systems.

Among other ecosystem traits, previous actions to drain forest soils cease, gradually leading to wetter or even periodically flooded forest soils. This may increase the emissions of the strong greenhouse gases methane and nitrous oxide from forest soils, thereby potentially off-setting the mitigating effect of carbon sequestration in restored wet forest soils.

Forests composition is changing toward increasing areal coverage of broadleaved species. Planting broadleaved tree species instead of coniferous species will alter nutrient dynamics in the soil over time which leads to differences in emission and consumption of nitrous oxide and methane between the contrasting forest types.

Methodology

Assessments of greenhouse gas inventories from forest soils also require robust methodologies to quantify the fluxes. We are therefore also involved in research dealing with methodological aspects of measuring and calculating fluxes of greenhouse gases from soils.

Research questions

We focus on the following research questions:

• How does restoration of natural hydrological conditions affect nitrous oxide and methane emissions from forest soils?

• What is the trade-off in global warming potential between carbon sequestration in soils and biomass and increased nitrous oxide and methane emissions following reversion to natural hydrological conditions?

• What is the role of tree species in regard to methane and nitrous oxide dynamics?

• How does methane and nitrous oxide processes in forest soils change during forest development following afforestation?

• What is the best way to design and operate techniques to measure trace gas fluxes from soils?

Collaboration

We collaborate with other Danish research institutes (e.g. NERI and Risø-DTU) as well as many European research institutes through participation in EU Framework Program 7 Integrated Projects (among others the Division of Atmospheric Sciences, Department of Physics, University of Helsinki).