Data collected during field experiments to investigate the effect of wildfires on greenhouse gas emissions across forests of differing ages in Sweden. Data comprise greenhouse gas measurements, soil horizon depth, bulk density, loss on ignition, pH, soil phosphorus, carbon and nitrogen, plant species cover, air temperature, soil temperature, soil moisture and surface leaf moisture. Greenhouse gas measurements were taken in the field. Soil cores were collected, then processed and analysed in the laboratory. Plant species cover was by visual estimate and final plant biomass was collected, dried, and weighed. Weather stations were used to collect temperature and moisture data. Data were collected from six Swedish boreal forest sites forming a chronosequence ranging in age from approximately 45 to 365 years since last wildfire. This part of the project used soil and plant property data, climatic data, and age since wildfire to investigate controls on forest floor greenhouse gas fluxes. The project ran from 2012 to 2015. Full details about this dataset can be found at https://doi.org/10.5285/f08a5de5-55d4-44de-90e1-94bb4f814054