The pattern of change in carbon (C) accumulation with forest ageing can vary greatly amongst different forest types. Documenting how C accumulates in various forest ecosystems in the absence of logging makes it possible to predict what would be the outcome of extending forest rotations or in dedicating more land to conservation on C storage. This study was conducted in boreal balsam fir (Abies balsamea (L.) Mill.) forests of Quebec, in eastern Canada. We compared carbon stocks in forest pools (aboveground (live) biomass, deadwood, FH horizon and mineral soil) of mature (70 years after harvest) vs old-growth stands (stands with no signs or history of human disturbance). Total ecosystem C stocks were not significantly different between mature and old-growth stands. However, as mature stands transition to old-growth stage, there appears to be a shift of C from live biomass pools towards deadwood and soil FH horizons. Coarse woody debris in old-growth stands were also found to be at more advanced stages of decay. The variability of C stocks was also high amongst old-growth stands; however, there was no obvious difference in structural diversity between mature and old-growth stands. Results suggest that ageing balsam fir stands through the lengthening of forest rotations (e.g. past the maturity age of 70 years) or by placing them under conservation, while not creating an important C sink, still contributes to maintain large forest C stocks across landscapes. Preserving or increasing the presence of old-growth forests is an important aspect of ecosystem-based forest management; our study concludes that it could also be compatible with sustainable forest carbon management.

中文翻译：

---

老化的森林和碳储存：北方香脂冷杉林的案例研究

随着森林老化，碳（C）积累的变化模式在不同森林类型之间可能有很大差异。记录在没有伐木的情况下 C 如何在各种森林生态系统中积累，可以预测延长森林轮作或将更多土地用于 C 储存保护的结果。这项研究是在加拿大东部魁北克的北方香脂冷杉 (Abies balsamea (L.) Mill.) 森林中进行的。我们比较了成熟（采伐后 70 年）森林池（地上（活）生物量、枯木、FH 层和矿质土壤）与老林（没有迹象或人类干扰历史的林）中的碳储量。成熟林和老林之间的生态系统总碳库没有显着差异。然而，随着成熟林分过渡到老生长期，碳似乎从活生物质池向枯木和土壤 FH 水平转移。还发现旧林中的粗木碎片处于更高级的腐烂阶段。在老林中，C 库存的变异性也很高；然而，成熟林和老林之间的结构多样性没有明显差异。结果表明，老化的香脂冷杉通过延长森林轮作（例如超过 70 年的成熟年龄）或将它们置于保护之下，虽然不会产生重要的碳汇，但仍有助于维持整个景观的大量森林碳储量。保护或增加原始森林的存在是基于生态系统的森林管理的一个重要方面；