China’s Tree Residue Sources and Quantity Estimation

In China, due to forest resource scarcity, the problem of timber supply shortage has been around for a long time. The recycling and utilization of tree residues may effectively alleviate the situation and will contribute to emissions reduction and environmental protection. Therefore, this study aims to identify the tree residue resources and estimates their quantity in order to provide a basis for related research, such as its comprehensive utilization. This study redefines and reclassifies tree residue resources, in particular, it adds three tree residue resources: tree seedling residue, sanitation felling residue and urban greening and trimmings. This study divides the forest final felling and bucking residue resource into the stumpage section and the non-stumpage section, respectively, scientifically selects values of the percent of merchantable volume and the proportion of non-stumpage biomass of the stumpage volume, separately estimates the quantity of bamboo felling, bucking and processing residues, classifies the forest product processing zone into the sawing section and the forest product processing section, and estimates the current waste wood recycling quantity by tracking the timber output of previous years. The estimation results for tree residue quantity indicate that China’s tree residue reached 511.63 Mt in 2015, of which the forest tending and thinning residue was 406.76 Mt, nearly four-fifths of the total tree residue. Among the 31 provinces (municipalities and autonomous regions), more than half (55.57%) of the potential reserve of tree residues is distributed in the 13 provinces of southern China, 25% in the 10 provinces in the north, and approximately 20% in the plain and hilly areas. During the 12th Five-Year Plan period, the tree residue reserves showed positive growth. In the past three years (2014–2016), all state-owned forestry farms and collective-owned natural forests stopped commercial felling gradually, which directly resulted in a reduction of log output, thereby also curbing the growth of tree residue to a certain extent. Since the log output has ceased to further decline from 2017, it is predicted that China’s tree residue will continue the upward trend.