Field investigations were performed in the central Lena Delta. In total, 25 sites were investigated. The sites were chosen to represent a variety of vegetation communities of the investigated region. 30 m² sample plots (sites) were demarcated in the most homogeneous locations. Heterogeneity was accommodated by roughly assorting vegetation into two to three vegetation types per sampling plot. Within each area of roughly estimated vegetation types we selected one 0.5 x 0.5 m subplot for representative ground-layer above-ground biomass (ABG) harvesting (major taxa and other). For moss and lichen AGB harvesting inside 0.5 x 0.5 m subplots representative 0.1 x 0.1 m subplots were chosen. All harvested AGB samples were weighed fresh in the field. In general, AGB samples with a weight of more than 15 g were subsampled. All samples were oven dried (60 °C, 24 h and weighed again). All ground-layer vegetation AGB assessments were calculated for the fifteen-meter radius plot in g/m² for each sample plot, see https://doi.pangaea.de/10.1594/PANGAEA.935923. All data was collected by scientists from Alfred Wegener Institute (AWI), Helmholtz Centre for Polar and Marine Research and University of Potsdam, Germany.