Forests and forest products can significantly contribute to climate change mitigation by stabilizing and even potentially decreasing the concentration of carbon dioxide (CO2) in the atmosphere. Harvested wood products (HWP) represent a common widespread and cost-efficient opportunity for negative emissions. After harvest, a significant fraction of the wood remains stored in HWPs for a period that can vary from some months to many decades, whereas atmospheric carbon (C) is immediately sequestered by vegetation re-growth. This temporal mismatch between oxidation of HWPs and C uptake by vegetation generates a net sink that lasts over time. The role of temporary carbon storage in forest products has been analysed and debated in the scientific literature, but detailed bottom-up studies mapping the fate of harvested materials and quantifying the associated emission profiles at national scales are rare. In this work, we quantify the net CO2 emissions and the temporary carbon storage in forest products in Norway, Sweden and Finland for the period 1960–2015, and investigate their correlation. We use a Chi square probability distribution to model the oxidation rate of C over time in HWPs, taking into consideration specific half-lives of each category of products. We model the forest regrowth and estimate the time-distributed C removal. We also integrate the specific HWP flows with an emission inventory database to quantify the associated life-cycle emissions of fossil CO2, CH4 and N2O. We find that assuming an instantaneous oxidation of HWPs would overestimate emissions of about 1.18 billion t CO2 (cumulative values for the three countries over the period 1960–2015).We also find that about 40 years after 1960, the starting year of our analysis, are sufficient to detect signs of negative emissions. The total amount of net CO2 emissions achieved in 2015 are about − 3.8 million t CO2, − 27.9 t CO2 and − 43.6 t CO2 in Norway, Sweden, and Finland, respectively. We argue for a more explicit accounting of the actual emission rates from HWPs in carbon balance studies and climate impact analysis of forestry systems and products, and a more transparent inclusion of the potential of HWP as negative emissions in perspective studies and scenarios. Simply assuming that all harvested carbon is instantaneously oxidized can lead to large biases and ultimately overlook the benefits of negative emissions of HWPs.

中文翻译：

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林木产品对负排放的贡献：挪威，瑞典和芬兰1960年至2015年的历史比较分析。

森林和森林产品可以通过稳定甚至降低大气中二氧化碳（CO2）的浓度来为缓解气候变化做出重大贡献。伐木产品（HWP）代表着普遍的，具有成本效益的负排放机会。收割后，大部分木材保留在HWP中的时间可能从几个月到几十年不等，而植被重新生长会立即隔离大气中的碳（C）。HWPs的氧化和植被对C的吸收之间的时间不匹配会产生一个随着时间而持续的净汇。在科学文献中，对暂时碳存储在林产品中的作用进行了分析和辩论，但是，很少有详细的自下而上的研究在全国范围内绘制出收获材料的命运并量化相关排放概况。在这项工作中，我们量化了挪威，瑞典和芬兰在1960–2015年期间的净二氧化碳排放量和林产品中的临时碳储存量，并调查了它们之间的相关性。考虑到每种产品的特定半衰期，我们使用卡方概率分布来模拟HWP中C随时间的氧化速率。我们对森林再生长进行建模，并估算时间分布的C清除量。我们还将特定的HWP流量与排放清单数据库集成在一起，以量化化石CO2，CH4和N2O的相关生命周期排放。我们发现，假设HWP的瞬时氧化会高估大约1的排放量。180亿吨CO2（这三个国家在1960-2015年期间的累计价值）。我们还发现，我们分析的开始之年1960年后的40年左右足以发现负排放的迹象。2015年，挪威，瑞典和芬兰的二氧化碳净排放总量分别约为380万吨，27.9吨和43.6吨。我们主张在碳平衡研究和林业系统及产品的气候影响分析中更明确地说明HWP的实际排放率，并在透视研究和情景中更透明地包含HWP作为负排放的潜力。简单地假设所有收获的碳都被瞬间氧化会导致较大的偏差，并最终忽略了HWP负排放的好处。