The aim of this paper was to determine the dry mass content in the fresh mass of leaves, trunks or branches and in the total woody aboveground biomass of shrubs forming the undergrowth of the stands in the Niepołomice Forest (southern Poland). The variability of the dry mass content in the analysed components was determined. For the prevailing species also its correlation with the individual's height and time at which samples were taken was investigated. The material comprised 744 samples, including 532 wood and 212 leaf samples, taken from the most common five shrub species: Corylus avellana, Frangula alnus, Padus avium, Padus serotina and Sorbus aucuparia. The shrubs were from 1 to 33 years old, and their height ranged from 0.3 to 9.9 m. It was shown that the dry mass content in leaves is significantly dependent on the shrub species, and in the case of F. alnus, P. avium and S. aucuparia on the height as well. The highest dry mass content was found in the leaves of C. avellana (39.3%), whereas the lowest – in F. alnus (25.5%). In case of F. alnus, the dry mass content depends on the time of sampling. The leaves collected in June had a significantly lower dry mass content than the ones sampled in subsequent months of the growing season. The dry mass content in the wood significantly depends on the shrub species and the analysed component, however the species−component interaction does not occur (tab. 4). The dry mass content in the trunk wood ranges from 50.3 (P. serotina and S. aucuparia) to 53.0% (P. avium) and exceeds that of the branch by from 1.0 (S. aucuparia) to 4.0% (P. avium). In the wood samples of F. alnus and S. aucuparia, taken between June and September, the dry mass content averaged at 47.3 and 48.7%, respectively, and was lower than in the samples taken between October and April, for which the respective means were 49.5 and 49.0%. In the case of F. alnus, the observed difference in the mean dry mass content is statistically significant at 0.05 level. The determined values of dry mass content in the fresh mass of individual components of the analysed shrubs can be used to find their dry mass as a basis for the calculation of the amount of accumulated carbon.