Wood has always been an indispensable material in human society throughout history. Its efficient utilization is even more crucial today in achieving the Sustainable Development Goals (SDGs). However, its production, trade, use, and recycling are seldom systematically assessed, with Germany being an exception due to the extensive work conducted by the University of Hamburg and the Thünen Institute over the years. To provide a more precise account of wood use, this study employs oven-dry metric tonne as the reference unit to construct a static wood flow based on the material flow analysis and wood resource balance in Germany in 2020. The Sankey diagrams comprehensively visualize the flow and stock of wood in various sectors, including forests, sawmills, pulp mills, buildings, energy, and waste. Results showed that forest felling volume exceeded growth due to significant wood demand and export, while forest carbon sinks increased because more hardwood was retained in German forests. The building and construction sector was the largest consumer of primary wood products, accounting for 52.1 % of the total, followed by furniture (29.5 %) and packaging (14.0 %). All waste paper was used to produce recycled fiber pulp, whereas only 14 % of waste wood was employed in particle board production. The woody biomass energy, amounting to 142.4 TWh, provided approximately 4.4 % of Germany's primary energy consumption, with around half of it used in private households. In addition to apparent data, this study also uses resource allocation, carbon storage, and cascade potential as examples to demonstrate that wood flow is applicable for further in-depth analysis, supporting wood efficient utilization. It can even be applied to any country and period with sufficient data and conversion factors, but here, they also prevented this study from comprehensively describing past and future wood flows.

中文翻译：

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用绝干公吨绘制 2020 年德国循环木材流量图

纵观历史，木材一直是人类社会不可或缺的材料。如今，其有效利用对于实现可持续发展目标 (SDG) 至关重要。然而，其生产、贸易、使用和回收很少得到系统评估，德国是一个例外，因为汉堡大学和图嫩研究所多年来进行了大量工作。为了更准确地核算木材使用情况，本研究以绝干公吨为参考单位，基于2020年德国物质流分析和木材资源平衡，构建了静态木材流。桑基图全面可视化了流向以及各个部门的木材库存，包括森林、锯木厂、纸浆厂、建筑、能源和废物。结果显示，由于大量的木材需求和出口，森林砍伐量超过了增长，而森林碳汇则由于德国森林中保留了更多的硬木而增加。建筑业是初级木制品的最大消费者，占总量的52.1%，其次是家具（29.5%）和包装（14.0%）。所有废纸都用于生产再生纤维纸浆，而只有 14% 的废木材用于生产刨花板。木质生物质能源达142.4太瓦时，约占德国一次能源消耗的4.4%，其中约一半用于私人家庭。除了表观数据外，本研究还以资源分配、碳储存和梯级潜力为例，证明木材流动适用于进一步深入分析，支持木材高效利用。它甚至可以适用于任何拥有足够数据和转换因子的国家和时期，但在这里，它们也阻止了这项研究全面描述过去和未来的木材流动。