Data from litterbag experiments carried out in southern Finland at six drained peatland forest sites and four mineral-soil forest sites. The sites represented different floristically determined site types that reflect different site nutrient regimes. Fine-roots (diameter < 2mm) of one to three tree species (Pinus sylvestris, Picea abies, Betula pubescens) per site, small roots (diameter 2-10 mm) of P. sylvestris in two peatland sites, and fine roots of one fern species (Dryopteris carthusiana) in one peatland site, were incubated for a maximum of five years with annual recoveries; incubation time varied in the site-species combinations. Litterbags covered 10-cm depth segments with either 20 cm or 30 cm depth range covered, depending on site.