Reducing net greenhouse gas emissions through conserving existing forest carbon stocks and encouraging additional uptake of carbon in existing and new forests have become important climate change mitigation tools. The contribution of harvested wood products (HWPs) to increasing carbon uptake has been recognised and approaches to quantifying this pool developed. In New Zealand, harvesting has more than doubled since 1990 while log exports have increased by a factor of 11 due to past afforestation and comparatively little expansion in domestic processing. This paper documents New Zealand’s application of the IPCC approaches for reporting contributions of the HWP pool to net emissions, in order to meet international greenhouse gas inventory reporting requirements. We examine the implications of the different approaches and assumptions used in calculating the HWP contribution and highlight model limitations. Choice of system boundary has a large impact for a country with a small domestic market and significant HWP exports. Under the Production approach used for New Zealand’s greenhouse gas inventory reporting, stock changes in planted forests and in HWPs both rank highly as key categories. The contribution from HWPs is even greater under the Atmospheric Flow approach, because emissions from exported HWPs are not included. Conversely the Stock Change approach minimises the contribution of HWPs because the domestic market is small. The use of country-specific data to backfill the time series from 1900 to 1960 has little impact but using country-specific parameters in place of IPCC defaults results in a smaller HWP sink for New Zealand. This is because of the dominance of plantation forestry based on a softwood mainly used in relatively short-lived products. The NZ HWP Model currently meets international inventory reporting requirements. Further disaggregation of the semi-finished HWP end uses both within New Zealand and in export markets is required to improve accuracy. Product end-uses and lifespans need to be continually assessed to capture changes. More extensive analyses that include the benefits of avoided emissions through product substitution and life cycle emissions from the forestry sector are required to fully assess the contribution of forests and forest products to climate change mitigation and a low emissions future.

中文翻译：

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估计新西兰的伐木产品的碳存量和存量变化。

通过保护现有森林的碳储量并鼓励在现有森林和新森林中进一步吸收碳来减少温室气体净排放量，已成为缓解气候变化的重要手段。人们已经认识到采伐的木材产品（HWP）对增加碳吸收的贡献，并开发了量化此库的方法。在新西兰，自1990年以来，采伐量增加了一倍以上，而原木出口由于过去的植树造林和国内加工的相对增长而增长了11倍。本文记录了新西兰采用IPCC方法报告HWP池对净排放的贡献，以满足国际温室气体清单报告的要求。我们检查了用于计算HWP贡献的不同方法和假设的含义，并重点介绍了模型局限性。系统边界的选择对一个国内市场很小，HWP出口量很大的国家有很大的影响。根据用于新西兰温室气体清单报告的生产方法，人工林和HWP的蓄积变化均被列为关键类别。在大气流量方法下，HWP的贡献更大，因为不包括出口HWP的排放。相反，由于国内市场很小，“库存变更”方法可将HWP的贡献降到最低。使用特定国家的数据回填1900年到1960年的时间序列几乎没有影响，但是使用特定国家的参数代替IPCC默认值会导致新西兰的HWP汇更小。这是因为基于主要用于较短寿命产品的软木的人工林的优势。NZ HWP模型当前满足国际库存报告要求。为了进一步提高准确性，需要对新西兰和出口市场上的半成品HWP最终用途进行进一步分类。需要不断评估产品的最终用途和寿命，以捕获变化。