Estimating available unused dead wood materials for heat generation in Mongolia: how much coal can unused dead wood materials substitute?

In this study, we estimated the technoeconomic availability of three types of dead trees, namely commercially fallen, normally fallen, and standing, in Mongolian subgroups. For dead trees of three major Mongolian tree species (Siberian larch, Scotch pine, and Asian white birch), lumber, firewood, and unused material as sources of energy were quantified and operational costs (marking, felling, skidding, transporting, loading/unloading, processing, and stumpage prices) were estimated. As a result, most Mongolian subgroups were profitable and suitable for the harvest of unused materials. Moreover, unused materials of dead trees can substitute nearly 5.45 million tons of coal, although it is not sufficient to meet the 0.6 years of coal demand across Mongolia. However, in some places, unused dead wood materials can completely substitute coal for decades. Therefore, although the heat utilization of woody biomass is not suitable for Mongolia as a whole, it is feasible in specific regions where forest resources are abundant, such as some Mongolian sub-provinces. Promoting the use of dead trees can reduce the risk of damage caused by wildfires and pests, which are serious problems in Mongolia, and keep the forests healthy. Furthermore, unused materials can generate new income opportunities, and the forest land can be well prepared by removing dead trees to promote planting for sustainable forest management. Finally, dead trees can be used as a resource until transition to sustainable forests with living trees.