Tree biomass data are essential for developing the biomass allometric models that are necessary for estimating carbon stock and for monitoring changes in forest biomass. In this ‘data article’ biomass records are presented for 240 Norway spruce trees (Picea abies (L.) Karst.). Trees were between 4 and 15 years of age and were sampled from 24 pure plantations located in Eastern Carpathians of Romania. Ten trees were sampled from each plantation using a cluster sampling method. For each tree, diameter at root collar height (D) and tree height (H) are provided as potential predictors for biomass. Oven-dried biomass is also recorded for the following partitions: stem (ST); branches (BR); needles (ND); roots (RT); as well as their combinations representing total aboveground biomass (AGB) and overall tree biomass (TB). Sampled trees were between 0.6 and 10.0 cm in diameter and between 53.0 and 552.0 cm in height. Total tree biomass ranged between 0.019 and 15.53 kg/tree. This dataset is related to the research article entitled “Site-effects on biomass allometric models for early growth plantations of Norway spruce (Picea abies (L.) Karst.)” (Dutcă et al., 2018) .