United States forests can contribute to national strategies for greenhouse gas reductions. The objective of this work was to evaluate forest sector climate change mitigation scenarios from 2018 to 2050 by applying a systems-based approach that accounts for net emissions across four interdependent components: (1) forest ecosystem, (2) land-use change, (3) harvested wood products, and (4) substitution benefits from using wood products and bioenergy. We assessed a range of land management and harvested wood product scenarios for two case studies in the U.S: coastal South Carolina and Northern Wisconsin. We integrated forest inventory and remotely-sensed disturbance data within a modelling framework consisting of a growth-and-yield driven ecosystem carbon model; a harvested wood products model that estimates emissions from commodity production, use and post-consumer treatment; and displacement factors to estimate avoided fossil fuel emissions. We estimated biophysical mitigation potential by comparing net emissions from land management and harvested wood products scenarios with a baseline (‘business as usual’) scenario. Baseline scenario results showed that the strength of the ecosystem carbon sink has been decreasing in the two sites due to age-related productivity declines and deforestation. Mitigation activities have the potential to lessen or delay the further reduction in the carbon sink. Results of the mitigation analysis indicated that scenarios reducing net forest area loss were most effective in South Carolina, while extending harvest rotations and increasing longer-lived wood products were most effective in Wisconsin. Scenarios aimed at increasing bioenergy use either increased or reduced net emissions within the 32-year analysis timeframe. It is critical to apply a systems approach to comprehensively assess net emissions from forest sector climate change mitigation scenarios. Although some scenarios produced a benefit by displacing emissions from fossil fuel energy or by substituting wood products for other materials, these benefits can be outweighed by increased carbon emissions in the forest or product systems. Maintaining forests as forests, extending rotations, and shifting commodities to longer-lived products had the strongest mitigation benefits over several decades. Carbon cycle impacts of bioenergy depend on timeframe, feedstocks, and alternative uses of biomass, and cannot be assumed carbon neutral.

中文翻译：

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评估美国林业景观气候变化缓解方案的系统方法。

美国森林可以为减少温室气体排放的国家战略做出贡献。这项工作的目标是通过应用基于系统的方法来评估林业部门从 2018 年到 2050 年的气候变化减缓情景，该方法考虑了四个相互依存的组成部分的净排放量：(1) 森林生态系统，(2) 土地利用变化，( 3）采伐的木材产品，以及（4）使用木材产品和生物能源的替代效益。我们评估了美国两个案例研究的一系列土地管理和采伐木材产品情景：南卡罗来纳州沿海地区和威斯康星州北部。我们将森林清查和遥感干扰数据整合到一个建模框架内，该框架由增长和产量驱动的生态系统碳模型组成；采伐木材产品模型，用于估算商品生产、使用和消费后处理的排放量；和位移因子来估计避免的化石燃料排放。我们通过将土地管理和采伐木材产品情景的净排放量与基线（“一切照旧”）情景进行比较，估算了生物物理缓解潜力。基线情景结果显示，由于与年龄相关的生产力下降和森林砍伐，两个地点的生态系统碳汇强度一直在下降。减缓活动有可能减少或推迟碳汇的进一步减少。缓解分析的结果表明，减少森林面积净损失的方案在南卡罗来纳州最有效，而延长采伐轮作和增加寿命较长的木材产品在威斯康星州最有效。旨在增加生物能源使用的情景会在 32 年的分析时间内增加或减少净排放量。运用系统方法全面评估林业部门气候变化减缓情景的净排放量至关重要。尽管某些情景通过取代化石燃料能源的排放或用木制品替代其他材料产生了效益，但这些效益可能会被森林或产品系统中碳排放的增加所抵消。几十年来，维持森林原样、延长轮伐期以及将商品转向寿命较长的产品具有最强的缓解效益。生物能源的碳循环影响取决于时间范围、原料和生物质的替代用途，并且不能假设碳中和。