Kobayashi Yuta, Akasaka Munemitsu
Field Science Center, Faculty of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Japan.
Institute of Global Innovation Research, Tokyo University of Agriculture and Technology, Fuchu, Japan.
Nat Ecol Evol. 2025 May 12. doi: 10.1038/s41559-025-02708-5.
Old trees, often living for hundreds or even thousands of years, play vital roles in maintaining biodiversity and ecosystem services. However, their extraordinary longevity occurs under rare circumstances, as most individuals succumb to mortality. From an optimal resource allocation perspective, species adopting a life-history strategy with a high potential maximum lifespan (PML) are expected to also have a higher life expectancy (LE). Here we developed a framework to assess the longevity of 1-cm-diameter trees and calculated the PML and LE for 53 major tree species in Japan. The results revealed that the PML (mean 378 years) was 4.7 times higher than the LE (mean 81 years). Both indices showed a positive correlation, with a regression slope of 0.34; however, the explanatory power of the model was low (R = 0.22). This can be attributed to the fact that LE exhibits a stronger negative response to climate-related habitat severity compared with that of PML. Our findings suggest two key points: (1) trees may adopt a hierarchical ordering of demographic parameters that prioritize long-term survival duration over average survival rate, and (2) considering this balance, which varies among species, could enhance the cost-effectiveness of ecosystem restoration.
古树通常能存活数百年甚至数千年，在维持生物多样性和生态系统服务方面发挥着至关重要的作用。然而，它们超长的寿命是在极为罕见的情况下出现的，因为大多数个体最终都会死亡。从最优资源分配的角度来看，采用具有高潜在最大寿命（PML）的生活史策略的物种，其预期寿命（LE）也会更高。在此，我们开发了一个框架来评估直径为1厘米的树木的寿命，并计算了日本53种主要树种的PML和LE。结果显示，PML（平均378年）比LE（平均81年）高出4.7倍。两个指标呈正相关，回归斜率为0.34；然而，该模型的解释力较低（R = 0.22）。这可以归因于与PML相比，LE对与气候相关的栖息地严峻程度表现出更强的负面反应。我们的研究结果表明了两个关键点：（1）树木可能采用一种人口统计学参数的分层排序方式，将长期存活时间置于平均存活率之上；（2）考虑到这种因物种而异的平衡，可能会提高生态系统恢复的成本效益。
