The drooping birch (Betula pendula) occupies a significant part of the territory of the forest fund, and in the forest-steppe zone it often performs the function of a dominant. Silver birch is one of the most intensively synthesizing aboveground phytomass tree species of the boreal zone. The purpose of the research is to identify patterns in the distribution of the phytomass of leaf blades of birch forest stands, taking into account regional standards, and to compare the results with the general tables of biological productivity. As a result, it was found that the tables of biological productivity for all categories of plantations (complete, modal) overestimate information about the final leaf weight. The closest results were obtained for modal forest stands in Siberia. The role of the structure in determining the phytomass of leaves can be from 5 to 35%, taking into account the distribution of trees by diameter. When assessing the phytomass of birch stands, it is necessary to strive to use local tables of the weight of individual tree fractions and distribution series that correspond to the maximum extent to the structure of these stands.