## 1 Introduction
### Estimates of Woody Biomass Resources in Russia and the Irkutsk Region  
According to current standards for waste generation [12; 13], about 75-127 million m\({}^{3}\) (101 \(\pm\) 26 million m\({}^{3}\)) of wood waste is generated annually in Russia (Table 3). The standard value of waste generation for pulp and paper production (only bark is taken into account) is 0.54 m\({}^{3}\)/t, for wood pulp--1.83 m\({}^{3}\)/t. The most probable total estimate of the volume of waste wood is 90-110 million m\({}^{3}\)/year. Table 4 shows the results of estimating the amount of wood waste generated annually in the Baikal region at the most likely waste generation rates. The calculations used specific data on the balances of timber used in the Irkutsk region [15], which were interpolated to the other two entities of the region under consideration. The calculated standard values of wood waste generation assumed in Table 4 are for logging--0.33 (including branches and twigs, trunk tops, bark, and stumps), for sawmilling--0.80 (including sawdust, lumpy waste, bark, and chips), for plywood production--1.84 (including sawdust, lumpy waste, trimmings, cores, bark, chips), and for pulp production--0.12 (the volume factor of bark on pulpwood bolts). \begin{table}
\begin{tabular}{l c c c c c c} \hline \hline \multirow{2}{*}{**Federal Subject**} & \multicolumn{6}{c}{**Years**} \\ \cline{2-7}  & **2010** & **2012** & **2014** & **2016** & **2018** & **2020** \\ \hline Irkutsk & 22.6 & 25.1 & 29.2 & 35.3 & 35.7 & 30.5 \\ Republic of & & & & & & \\ Buryatiya & 2.0 & 2.3 & 2.3 & 3.1 & 3.0 & 2.2 \\ Zabaykalsky Krai & 2.0 & 2.4 & 2.2 & 2.1 & 1.7 & 1.5 \\ \hline \hline \end{tabular} Note: Source: EMISS (Unified Interdepartmental Information and Statistical System) [17].  
\end{table} 
Table 2: Logging volumes in the Baikal region (2010–2020), million m\({}^{3}\)/year. \begin{table}
\begin{tabular}{l c c c} \hline \hline \multirow{2}{*}{**Products**} & \multirow{2}{*}{**Waste Generation Standard**} & \multicolumn{2}{c}{**Manufacturing (2016–2020)**} & \multirow{2}{*}{**Waste Products**} \\ \cline{1-2} Logging & 0.226–0.344 & 213.8–238.6 & 48.3–82.1 \\ \hline Lumber & 0.46–0.90 & 23.7–29.3 & 10.9–26.4 \\ \hline Plywood & 1.55–1.84 & 3.8–4.2 & 5.9–7.7 \\ \hline Containers & 2.76 & 0.4–0.5 & 1.1–1.4 \\ \hline Cellulose & 0.12 & 37.2–39.4 & 4.5–4.7 \\ \hline Wood pulp & 0.70 & 6.0–6.3 & 4.2–4.4 \\ \hline Total & & 285.0–318.3 & 74.9–126.7 \\ \hline \hline \end{tabular} Note: data on paper pulp and wood pulp are converted from tons to cubic meters according to the following ratios: 1 ton of cellulose = 4.52 m\({}^{3}\), 1 ton of wood pulp = 2.62 m\({}^{3}\)[12; 13].  
\end{table} 
Table 3: Estimate of the volume of wood waste in Russia, million m\({}^{3}\)/year. The main resources of waste wood fuel are concentrated in the Irkutsk region; in Buryatia and Zabaykalsky Krai they are an order of magnitude smaller. The total volume of wood waste is about 19 million m\({}^{3}\), including almost 90% in the Irkutsk region. The bulk of waste is logging waste (13.4 million m\({}^{3}\)/year). With a heating value of 11-15 MJ/kg (for wet and naturally dried wood, respectively) [22] and a waste density of 850 kg/m\({}^{3}\), its energy equivalent is 125-171 PJ, or 3-4 million tons of oil equivalent (toe). The energy equivalent of other waste products at a heating value of 9.5-11 MJ/kg and a waste density of 800 kg/m\({}^{3}\) is estimated to be 43-49 PJ, or 1.0-1.2 million toe. The total energy equivalent of wood waste is about 168-220 PJ (4.0-5.3 million toe). A relatively new and promising product of wood waste processing is currently pellet fuels (pellets). Pellets are widely used in economically developed countries of Europe, America, and Asia for burning for heating purposes as a coal substitute (or together with it) and for electricity generation. Almost all Russian pellet producers export their products to the European Union, Japan, and South Korea.