There are high estimates of the potential climate change mitigation opportunity of using wood products. A significant part of those estimates depends on long-lived wood products in the construction sector replacing concrete, steel, and other non-renewable goods. Often the climate change mitigation benefits of this substitution are presented and quantified in the form of displacement factors. A displacement factor is numerically quantified as the reduction in emissions achieved per unit of wood used, representing the efficiency of biomass in decreasing greenhouse gas emissions. The substitution benefit for a given wood use scenario is then represented as the estimated change in emissions from baseline in a study’s modelling framework. The purpose of this review is to identify and assess the central economic and technical assumptions underlying forest carbon accounting and life cycle assessments that use displacement factors or similar simple methods. Four assumptions in the way displacement factors are employed are analyzed: (1) changes in harvest or production rates will lead to a corresponding change in consumption of wood products, (2) wood building products are substitutable for concrete and steel, (3) the same mix of products could be produced from increased harvest rates, and (4) there are no market responses to increased wood use. After outlining these assumptions, we conclude suggesting that many studies assessing forest management or products for climate change mitigation depend on a suite of assumptions that the literature either does not support or only partially supports. Therefore, we encourage the research community to develop a more sophisticated model of the building sectors and their products. In the meantime, recognizing these assumptions has allowed us to identify some structural, production, and policy-based changes to the construction industry that could help realize the climate change mitigation potential of wood products.

中文翻译：

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木制品碳替代效益：对假设的批判性审查

对使用木制品的潜在气候变化缓解机会有很高的估计。这些估计的很大一部分取决于建筑行业的长寿命木制品替代混凝土、钢材和其他不可再生产品。这种替代的减缓气候变化的好处通常以置换因子的形式呈现和量化。置换因子在数字上量化为每单位木材使用所实现的排放减少，代表生物质在减少温室气体排放方面的效率。然后，给定木材使用情景的替代效益表示为研究建模框架中排放量相对于基线的估计变化。本次审查的目的是确定和评估使用置换因子或类似简单方法的森林碳核算和生命周期评估的核心经济和技术假设。分析了采用置换因子的方式的四个假设：（1）收获或生产率的变化将导致木制品消费的相应变化，（2）木建筑产品可以替代混凝土和钢材，（3）提高采伐率可以生产相同的产品组合，并且 (4) 市场对木材使用量的增加没有反应。在概述了这些假设之后，我们得出结论认为，许多评估森林管理或减缓气候变化产品的研究依赖于一系列文献不支持或仅部分支持的假设。因此，我们鼓励研究界开发更复杂的建筑部门及其产品模型。与此同时，认识到这些假设使我们能够确定建筑行业的一些结构、生产和基于政策的变化，这些变化可能有助于实现木制品减缓气候变化的潜力。