Natural forests cover approximately 29% of New Zealand’s landmass and represent a large terrestrial carbon pool. In 2002 New Zealand implemented its first representative plot-based natural forest inventory to assess carbon stocks and stock changes in these mostly undisturbed old-growth forests. Although previous studies have provided estimates of biomass or carbon stocks, these were either not fully representative or lacked data from important pools such as dead wood (coarse woody debris). The current analysis provides the most complete estimates of carbon stocks and stock changes in natural forests in New Zealand. We present estimates of per hectare carbon stocks and stock changes in live and dead organic matter pools excluding soil carbon based on the first two measurement cycles of the New Zealand Natural Forest Inventory carried out from 2002 to 2014. These show that New Zealand’s natural forests are in balance and are neither a carbon source nor a carbon sink. The average total carbon stock was 227.0 ± 14.4 tC·ha− 1 (95% C.I.) and did not change significantly in the 7.7 years between measurements with the net annual change estimated to be 0.03 ± 0.18 tC·ha− 1·yr− 1. There was a wide variation in carbon stocks between forest groups. Regenerating forest had an averaged carbon stock of only 53.6 ± 9.4 tC·ha− 1 but had a significant sequestration rate of 0.63 ± 0.25 tC·ha− 1·yr− 1, while tall forest had an average carbon stock of 252.4 ± 15.5 tC·ha− 1, but its sequestration rate did not differ significantly from zero (− 0.06 ± 0.20 tC·ha− 1·yr− 1). The forest alliance with the largest average carbon stock in above and below ground live and dead organic matter pools was silver beech-red beech-kamahi forest carrying 360.5 ± 34.6 tC·ha− 1. Dead wood and litter comprised 27% of the total carbon stock. New Zealand’s Natural Forest Inventory provides estimates of carbon stocks including estimates for difficult to measure pools such as dead wood and roots. It also provides estimates of uncertainties including effects of model prediction error and sampling variation between plots. Importantly it shows that on a national level New Zealand’s natural forests are in balance. Nevertheless, this is a nationally important carbon pool that requires continuous monitoring to identify potential negative or positive changes.

中文翻译：

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新西兰的天然森林——处于国家平衡状态的大型陆地碳库

天然森林约占新西兰陆地面积的 29%，是一个巨大的陆地碳库。2002 年，新西兰实施了第一个具有代表性的基于地块的天然林清单，以评估这些大部分未受干扰的原始森林中的碳储量和储量变化。尽管以前的研究提供了生物量或碳储量的估计值，但这些要么不完全具有代表性，要么缺乏来自死木（粗木屑）等重要池的数据。当前的分析提供了对新西兰天然林碳库和库变化的最完整估计。我们根据 2002 年至 2014 年新西兰天然林清单的前两个测量周期，提供了除土壤碳之外的活和死有机物质库中每公顷碳储量和储量变化的估计值。这些表明新西兰的天然林是平衡，既不是碳源也不是碳汇。平均总碳储量为 227.0 ± 14.4 tC·ha− 1 (95% CI)，并且在两次测量之间的 7.7 年中没有显着变化，净年度变化估计为 0.03 ± 0.18 tC·ha− 1·yr− 1 . 森林组之间的碳储量差异很大。再生林的平均碳储量仅为 53.6 ± 9.4 tC·ha− 1，但固存率为 0.63 ± 0.25 tC·ha− 1·yr− 1，而高大森林的平均碳储量为 252.4 ± 15.5 tC ·ha− 1, 但其封存率与零没有显着差异（- 0.06 ± 0.20 tC·ha- 1·yr- 1）。地上和地下活和死有机物池平均碳储量最大的森林联盟是银山毛榉-红山毛榉-kamahi 森林，承载 360.5 ± 34.6 tC·ha− 1。死木和枯枝落叶占总碳的 27%股票。新西兰的天然林清单提供了碳储量的估计值，包括对死木和根等难以测量的库的估计值。它还提供了不确定性的估计，包括模型预测误差的影响和地块之间的抽样变化。重要的是，它表明新西兰的天然森林在全国范围内处于平衡状态。尽管如此，