This data set contains three files (.txt format). Two of the files contain stand characteristics, above- and below-ground biomass, and above- and below-ground production allocation data for Scots pine (Pinus sylvestris) forests near Jädraås, Sweden. One file is for a young regenerating forest (14-20 years old) and the other is for an old-growth forest (120-125 years old). The field measurements were made by destructive and non-destructive methods between 1973 and 1983. The third file contains climate data recorded at the Jädraås site from 1974 through 1990.The research was conducted under the auspices of SWECON (Swedish Coniferous Forest Biome) Project to enhance understanding of plant biomass dynamics and factors regulating plant growth. Most of the research concerned plant and vegetation processes, but particular interest was also given to soil processes, consumption processes, and energy and water exchange in the canopy and the soil.Total net primary production (NPP) in the young forest was estimated at 860 g/m2/year (above-ground = 372 g/m2/year; below-ground = 488 g/m2/year). NPP for the old-growth forest was not calculated; however, the data set contains estimates of branch and trunk growth (43 g/m2/year and 106 g/m2/year, respectively), annual litterfall (135-162 g/m2/year), needle grazing loss (1.55 g/m2/year), fine tree root production (188 g/m2/year), and understory root production (30 g/m2/year).Revision Notes: The NPP data file has been split into two files, one for the young regenerating forest and one for old-growth forest. The data files have been revised to correct previously reported data and information and to add new data from published sources. Please see the ORNL DAAC Data Set Change Information file for more information.