Energy function of forest ecosystems is an important component of the system of their ecosystem functions. In this context, quantitative and qualitative assessment of the energy function of beech forests in Bukovyna Precarpathian region as an information tool for ensuring efficient forest management on the basis of the sustainable development paradigm is proposed within the framework of this research. The main indicator characterizing the energy function of forests is their energy content, i.e. the energy content of live biomass components, because the key processes that ensure the effective functioning of any ecosystem on Earth, including forest ecosystems, are the processes related to energy input, transformation and use. As a result of the research, quantitative indicators of energy content in live biomass of beech stands within the study region as well as their energy productivity were assessed. In total, over 230 PJ of energy have been accumulated in beech stands of the study region. Tree stands of seed natural origin account for about 97 % of the total amount of energy accumulated in live biomass of beech stands in the study region. The energy productivity of the stands under research is about 15 PJ∙year-1. At the same time, mid-aged stands feature the highest energy productivity – 260 GJ∙ha-1∙year-1. The energy productivity of mature and over mature beech stands is at the level of 200 GJ∙ha-1∙year-1. In rich (D2, D3) and relatively rich (C2, C3) conditions, quantitative values of energy productivity are respectively 260 and 220 GJ∙ha-1∙year-1. It has been found that annually beech stands form the energy potential of wood biomass ranging from 3.6 to 1.5 PJ depending on the type of potential.