『Abstract
　The magnitude of greenhouse gas (GHG) flux rates may be important in wet and intermediate wet forest soils, but published estimates are scarce. We studied the surface exchange of methane (CH4) and nitrous oxide (N2O) from soil along toposequences in two temperate deciduous forest catchments: Strodam（oには/が重なる） and Vestskoven. The soil water regime ranged from fully saturated to aerated within the catchments. At Strodam（oには/が重なる） the largest mean flux rates of N2O (15μg N2O-N m^-2 h^-1) were measured at volumetric soil water contents (SWC) between 40 and 60% and associated with low soil pH compared to smaller mean flux rates of 0-5μg N2O-N m^-2 h^-1 for drier (SWC＜40%) and wet conditions (SWC＞80%). At Vestskoven the same response of N2O to soil water content was observed. Average CH4 flux rates were highly variable along the toposequences (-17 to 536μg CH4-C m^-2 h^-1) but emissions were only observed above soil water content of 45%. Scaled flux rates of both GHGs to catchment level resulted in emission of 322 and 211 kg CO2-equivalents ha^-1 year^-1 for Strodam（oには/が重なる） and Vestskoven, respectively, with N2O contributing the most at both sites. Although the wet and intermediate wet forest soils occupied less than half the catchment area at both sites, the global warming potential (GWP) derived from N2O and CH4 was more than doubled when accounting for these wet areas in the catchments. The results stress the importance of wet soils in assessments of forest soil global warming potentials, as even small proportions of wet soils contributes substantially to the emissions of N2O and CH4.

Keywords: Drainage; Forest soil; Methane; Nitrous oxide; Scaling; Wet soils』

Introduction
Materials and methods
　Study site
　Field design
　Soil conditions along the transects
　Greenhouse gas exchange
　　Field measurements of gas exchange
　　Gas chromatography and calculation of gas flux rates
　Scaling of greenhouse gas flux rates and drainage scenarios
　　Scaling of greenhouse gas flux rates
　　Drainage scenarios
　Statistics and data analysis
Results
　Soil characteristics along the toposequences
　Hydrological changes along the toposequences
　N2O flux rates
　CH4 flux rates
　Response functions for N2O and CH4
　Scaling of hydrology and greenhouse gas flux rates to catchment level
　Drainage scenarios
Discussion
　N2O flux rates
　CH4 flux rates
　Scaling of hydrology and greenhouse gas flux rate
　Importance of wet forest soils for greenhouse gas emissions
　Effect of altering groundwater table on global warming potential of the forest soil
Conclusion
Acknowledgments
References