AimsSlow or failed tree regeneration after forest disturbance is increasingly observed in the central European Alps, potentially amplifying the carbon (C) loss from disturbance. We aimed at quantifying C dynamics of a poorly regenerating disturbance site with a special focus on the role of non-woody ground vegetation.MethodsSoil CO2 efflux, fine root biomass, ground vegetation biomass, tree increment and litter input were assessed in (i) an undisturbed section of a ~ 110 years old Norway spruce stand, (ii) in a disturbed section which was clear-cut six years ago (no tree regeneration), and (iii) in a disturbed section which was clear-cut three years ago (no tree regeneration).ResultsTotal soil CO2 efflux was similar across all stand sections (8.5 ± 0.2 to 8.9 ± 0.3 t C ha−1 yr.−1). The undisturbed forest served as atmospheric C sink (2.1 t C ha−1 yr.−1), whereas both clearings were C sources to the atmosphere. The source strength three years after disturbance (−5.5 t C ha−1 yr.−1) was almost twice as high as six years after disturbance (−2.9 t C ha−1 yr.−1), with declining heterotrophic soil respiration and the high productivity of dense graminoid ground vegetation mitigating C loss.ConclusionsC loss after disturbance decreases with time and ground vegetation growth. Dense non-woody ground vegetation cover can hamper tree regeneration but simultaneously decrease the ecosystem C loss. The role of ground vegetation should be more explicitly taken into account in forest C budgets assessing disturbance effects.

中文翻译：

---

密集的地面植被生长减轻了森林干扰后的碳损失

在中欧阿尔卑斯山越来越多地观察到森林干扰后树木再生缓慢或失败，这可能会放大干扰造成的碳 (C) 损失。我们的目标是量化一个再生不良的干扰场地的 C 动态，特别关注非木本地面植被的作用。大约 110 年树龄的挪威云杉林的未受干扰部分，(ii) 六年前被砍伐的受干扰部分（没有树木再生），以及 (iii) 三年前被砍伐的受干扰部分（没有树木再生）。结果所有林分的总土壤 CO2 流出量相似（8.5 ± 0.2 到 8.9 ± 0.3 t C ha-1 yr.-1）。未受干扰的森林作为大气 C 汇 (2. 1 t C ha-1 yr.-1)，而这两个空地都是大气的来源。干扰后三年（-5.5 t C ha-1 yr.-1）的源强度几乎是干扰后六年（-2.9 t C ha-1 yr.-1）的两倍，异养土壤呼吸和茂密的禾本科地面植被的高生产力减轻了 C 损失。结论干扰后的 C 损失随着时间和地面植被的生长而减少。密集的非木质地面植被覆盖会阻碍树木再生，但同时会减少生态系统 C 的损失。在评估影响的森林碳预算中应更明确地考虑地面植被的作用。-1) 几乎是干扰后六年的两倍（-2.9 t C ha-1 yr.-1），异养土壤呼吸下降和茂密的禾本科地面植被的高生产力减轻了 C 损失。结论干扰后的 C 损失减少随着时间和地面植被的生长。密集的非木质地面植被覆盖会阻碍树木再生，但同时会减少生态系统 C 的损失。在评估影响的森林碳预算中应更明确地考虑地面植被的作用。-1) 几乎是干扰后六年的两倍（-2.9 t C ha-1 yr.-1），异养土壤呼吸下降和茂密的禾本科地面植被的高生产力减轻了 C 损失。结论干扰后的 C 损失减少随着时间和地面植被的生长。密集的非木质地面植被覆盖会阻碍树木再生，但同时会减少生态系统 C 的损失。在评估影响的森林碳预算中应更明确地考虑地面植被的作用。密集的非木质地面植被覆盖会阻碍树木再生，但同时会减少生态系统 C 的损失。在评估影响的森林碳预算中应更明确地考虑地面植被的作用。密集的非木质地面植被覆盖会阻碍树木再生，但同时会减少生态系统 C 的损失。在评估影响的森林碳预算中应更明确地考虑地面植被的作用。