Rapid industrial development, the growth of the population on the planet and the reduction of fossil energy resources over the past century have led to an unstable supply of energy resources in most countries of the world. Under these conditions, the European Commission plans to increase the share of renewable energy to 30 % over the next half century. Today in Ukraine there are several sources of obtaining energy wood raw materials. First of all, it is fuel wood, chipped residue and wood that has not been removed from the forest. There are two main areas of bioenergy: the energy of the ecosystem and the energy that is concentrated in wood and can be used as fuel. In our research, the forest litter of the bedding refers to the direction of "energy of the ecosystem", and the mortmass snags , logs , and branches to the components that can be used by man as an additional source of energy. Establishing the amount of energy accumulated in the forest ecosystem is possible, first of all, due to the estimation of phytomass and mortmass plantings. It is known that the first attempts of such studies were performed by simple extrapolation of phytomass estimation data on selected test areas to significant forest regions with significant overestimation of results. The most tested at the present stage of the study of the features of the accumulation of living organic matter in forest systems are the methods associated with the evaluation of relevant indicators through the regression modeling of the components of fractions in absolute values or using transfer coefficients. The purpose of the study is to establish quantitative indices of accumulated energy in mortmass of birch forestry. Material and methods of research. In order to determine the components of the above ground mortmass, 30 temporary trial areas were laid in modal birches of in Chernihiv region. On each test area, an estimation of the classical inventory indices of the planting, also the established reserves, the structure of phytomass and mortmass. To calculate the components of mortmass, data from a solid list of trunks on the temporary trial areas and biometric parameters of model trees using the PERTA software were used. To determine the area of birch forestry in the Chernihiv region, data from the production association «Ukrderzhlisproekt» (2011) database was used. Conclusions According to the results of the research, the energy content of the dry mortmass snags of birch trees, which varies from 3,9 GJ·ha -1 to 108 GJ·ha -1 , in dry branches from 17,6 GJ·ha -1 to 12,5 GJ·ha -1 . The energy content of the mortmass logs can vary from 1,1 GJ·ha -1 to 103 GJ·ha -1 , in the mortmass of rough branches it changes from 0,5 GJ·ha -1 in young to 26 GJ·ha -1 in ripe birch forestry. Thus, the obtained results will contribute to the practical implementation of the development of bioenergy in Ukraine as one of the most promising directions for solving energy problems, and the developed reference materials can be used during scientific, ecological, forestry substantiation of the expanded use of forest energy resources of birch laying in Chernihiv region. Key words: snags , logs , branches, forest litter, average diameter, average height, basic density, classes of destruction