Summary Carbon reserves are distributed throughout plant cells allowing past photosynthesis to fuel current metabolism. In trees, comparing the radiocarbon (Δ14C) of reserves to the atmospheric bomb spike can trace reserve ages. We synthesized Δ14C observations of stem reserves in nine tree species, fitting a new process model of reserve building. We asked how the distribution, mixing, and turnover of reserves vary across trees and species. We also explored how stress (drought and aridity) and disturbance (fire and bark beetles) perturb reserves. Given sufficient sapwood, young (< 1 yr) and old (20–60+ yr) reserves were simultaneously present in single trees, including ‘prebomb’ reserves in two conifers. The process model suggested that most reserves are deeply mixed (30.2 ± 21.7 rings) and then respired (2.7 ± 3.5‐yr turnover time). Disturbance strongly increased Δ14C mean ages of reserves (+15–35 yr), while drought and aridity effects on mixing and turnover were species‐dependent. Fire recovery in Sequoia sempervirens also appears to involve previously unobserved outward mixing of old reserves. Deep mixing and rapid turnover indicate most photosynthate is rapidly metabolized. Yet ecological variation in reserve ages is enormous, perhaps driven by stress and disturbance. Across species, maximum reserve ages appear primarily constrained by sapwood longevity, and thus old reserves are probably widespread.

中文翻译：

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几十年来的碳储量在树种中广泛存在，仅受边材寿命的限制


摘要 碳储量分布在整个植物细胞中，使过去的光合作用能够为当前的新陈代谢提供动力。在树木中，将储量的放射性碳 （Δ14C） 与大气炸弹峰值进行比较可以追踪储量年龄。我们综合了 9 个树种茎储量的 Δ14C 观测值，拟合了新的储量建设过程模型。我们询问了保护区的分布、混合和周转如何因树木和物种而异。我们还探讨了压力（干旱和干旱）和干扰（火甲虫和树皮甲虫）如何扰乱保护区。如果边材充足，幼树（x3C 1 年）和老树（20-60+ 年）储量同时存在于单棵树中，包括两棵针叶树的“炸弹前”储量。过程模型表明，大多数储量是深度混合的（30.2 ± 21.7 环），然后是呼吸的（2.7 ± 3.5 年的周转时间）。干扰大大增加了 Δ14C 储量的平均年龄（+15-35 年），而干旱和干旱对混合和周转的影响与物种有关。红杉 （Sequoia sempervirens） 的火灾恢复似乎也涉及以前未观察到的旧储备的向外混合。深度混合和快速周转表明大多数光合产物被迅速代谢。然而，保护区年龄的生态差异是巨大的，这可能是由压力和干扰驱动的。在各个物种中，最大保护区年龄似乎主要受边材寿命的限制，因此旧保护区可能普遍存在。