Data Calculations RevA 2025.02.23.xlsx

<b>Abstract: </b>The climate emergency calls for carbon drawdown to be applied at scale to offset the ‘hard to abate’ emission reductions that threaten Net Zero. The use of biogenic materials in construction promises benefits in terms of low embodied carbon (EC), but timber harvested today only sequestered atmospheric carbon (AC) in the <i>past</i>. A reduction in <i>future</i> AC concentration is only possible from today, and harvesting timber harms a forest’s ability to sequester carbon in the future, unless a level of afforestation can be guaranteed. Current Whole Life Carbon (WLC) assessment methodologies confuse the perceived value of past sequestration, making it seem equivalent to EC, or implying a guarantee of future AC. This study seeks to connect these two opposing elements by finding a forest management ‘success’ value (F_S) at which harvesting losses are outweighed by future sequestration, and a net benefit (in future AC terms) can be justifiably claimed. The research proposes a measure of forestry success (a standard established in terms of net sequestration per hectare) and cumulatively offsets losses through harvest against additional drawdown achieved in a well-managed forest. The results show that current boreal forest management regimes do not guarantee a net benefit, but that only modest improvements from a contemporary baseline would be required to see a net benefit by 2050. Recommendations are made to establish a carbon-focused standard for forestry management to replace current binary sustainability accreditations.

**摘要：** 气候紧急状态要求大规模开展碳移除工作，以抵消那些难以削减的排放量，而这些排放正威胁着净零排放目标。建筑领域使用生物基材料有望在降低隐含碳（Embodied Carbon, EC）方面带来益处，但当前采伐的木材仅在**过去**固存了大气碳（Atmospheric Carbon, AC）。只有从当下开始，才能实现**未来**大气碳浓度的降低；而采伐木材会损害森林未来的固碳能力，除非能够保障开展相应规模的造林活动。当前的全生命周期碳（Whole Life Carbon, WLC）评估方法混淆了对过去固碳价值的认知，使其看似与隐含碳等价，或是暗含了对未来大气碳固存的保障。本研究旨在将这两种对立要素联系起来，通过确定森林管理“成功”值（F_S）——当该值下未来固碳量足以抵消采伐带来的碳损失时，便可合理宣称实现了净收益（以未来大气碳固存量计）。本研究提出了一项森林经营成效衡量标准（以单位公顷净固碳量为基准），并将采伐造成的碳损失与经营良好的森林所实现的额外碳移除量进行累计抵消。研究结果显示，当前的北方针叶林管理模式无法保障实现净收益，但只需在当前基准线基础上做出小幅改进，即可在2050年前实现净收益。本研究建议制定以碳为核心的森林经营标准，以取代现行的二元可持续性认证体系。