Permafrost melting threatens to release vast amounts of C to the atmosphere, but exact interactions between ecosystem disturbances, permafrost melting, SOM decomposition and vegetation productivity are not known. The acceleration of biological processes such as decomposition and below ground C input and C allocation of trees and associated priming effects following forest fires in the arctic region may lead to large changes in CO₂, CH₄ and N₂O fluxes. These processes evidently alter the C and N turnover rate of the remaining SOM, which may ultimately affect the net primary production (NPP) of the forest ecosystem causing feedback mechanisms to C uptake and eventually atmospheric CO2 concentration.

AIMS

1. We will study how the forest fires affect the biologically active layer on top of the permafrost by measuring biogeochemical properties of the soil e.g. soil carbon and nitrogen content, microbial species composition as well as greenhouse gas fluxes.
2. We will also measure the changes in soil surface reflectance and the depth of the permafrost layer
3. Finally, we will combine the measured data for developing and parameterizing process based ecosystem models to predict the effect of forest fires on forest carbon and nitrogen dynamics in the arctic.

METHODS

Our multidisciplinary research project combines detailed soil process studies to remote sensing and ecosystem modelling, and it produces new research knowledge on the multidimensional change processes in the arctic region and the factors affecting them.

The project will be based on intensive field measurement campaigns which will be carried out in arctic forests in Northern Yukon Canada, in Tura in Central Siberia and in Värriö research station in Lapland in Finland. The campaigns will be carried out in forests with different time since the last fire.

PARTNERS

The international partners in the ARCTICFIRE are University of Saskatchewan, Russian Academy of Sciences Sukachev institute of forests, Memorial University of New Foundland and the Austrian Academy of Sciences Comission for interdisciplinary studies. We will carry out our measurements in Canada in the areas of the indigenous people living in the study areas in the arctic.