樹木的長壽 On tree longevity
Distribution of tree species with longevity > 2000 yr in relation to average annual air temperature and total annual precipitation, which were also used to draw biome boundaries (modified from Fig. 2.22 in Chapin III et al., 2011). Fitzroya cupressoides (blue circle); Juniperus przewalskii (green circle); Pinus longaeva and Pinus aristata (gray triangles); Sequoia sempervirens (cyan triangle); Sequoiadendron giganteum (orange triangle); Taxodium disticum (red triangle). Climatic data for the USA were obtained from the online public-domain version of the PRISM dataset (Daly et al., 2008). The map inset shows tree species locations. 
Summary representation of the six conifer species that can live more than 2000 yr. The phylogenetic tree graph was obtained using the Interactive Tree Of Life online tool (Letunic & Bork, 2019); taxonomic data are from Leslie et al. (2018). Clades highlighted in red are mentioned in the text because they include at least one species whose longevity exceeds 2000 yr. 
Examples of trees that have been found to be the oldest (left side) but not the largest (right side) in the Italian Apennines. When shown for the same species, the two ring-width time-series plots have identical scales. Top panel: for European beech (Fagus sylvatica L.), the oldest tree (Michele) was found in the high-mountain old-growth forest of Pollino National Park (Piovesan et al., 2019a), even though a larger and much younger beech is present on Mount Cimino in central Italy (Piovesan et al., 2008). Middle panel: for Heldreich’s pine (Pinus heldreichii Christ), the oldest tree in Europe (Italus) was found in Pollino National Park (Piovesan et al., 2018b), where a larger pine was considerably younger. Bottom panel: for sessile oak (Quercus petraea (Matt.) Liebl.), the oldest oak (Demeter) found to date is located at 1700 m elevation, compared to a larger but younger one at 1300 m elevation in Aspromonte National Park (Piovesan et al., 2020). DBH, diameter at breast height. 
Photographs of stem cross-sections with roughly equal diameter that were taken from saplings of western larch (Larix occidentalis Nutt.) cut in 2014 at Snow Bowl (western Montana, USA; photo credit: S. Hood): (right) c. 10-yr-old tree growing in an area that had been thinned; (left) c. 90-yr-old tree growing in a control area. The scale of the two photographs is not exactly the same, as can be inferred from the ruler images beneath the sections.
Comparison of growth rates for the oldest trees and for the largest trees. (a) Stem size, age and growth rate of the ten largest and the 10 oldest giant sequoias in Huntington (1914) compared to the General Sherman Tree (courtesy of N. Stephenson; data from Stephenson & Demetry, 1995). On average (blue segments), the 10 oldest sequoias were almost 1000 yr older than the 10 largest ones, but were c. 1 m less in diameter because of slower growth rates (average ring widths of c 0.5–1 mm compared to c 0.8–2.0 mm). (b) Cumulative growth (basal area) trajectories of managed (orange lines) and secondary old-growth (blue lines) montane beech forests (n = number of trees) in Marsica (Abruzzo, Italy). The average of the 13 oldest trees (red for managed forests, black for secondary old-growth forests) highlights faster tree growth histories caused by human impacts (i.e. logging). 
Photographs of strip-bark trees, with only a fraction of the trunk and crown still alive: (left) single-needle pinyon (Pinus monophylla Torr. & Frém) in the Great Basin of North America; (right) sessile oak (Quercus petraea (Matt.) Liebl.) in the Aspromonte Mountains of southern Italy.
Summary
Large, majestic trees are iconic symbols of great age among living organisms. Published evidence suggests that trees do not die because of genetically programmed senescence in their meristems, but rather are killed by an external agent or a disturbance event. Long tree lifespans are therefore allowed by specific combinations of life history traits within realized niches that support resistance to, or avoidance of, extrinsic mortality. Another requirement for trees to achieve their maximum longevity is either sustained growth over extended periods of time or at least the capacity to increase their growth rates when conditions allow it. The growth plasticity and modularity of trees can then be viewed as an evolutionary advantage that allows them to survive and reproduce for centuries and millennia. As more and more scientific information is systematically collected on tree ages under various ecological settings, it is becoming clear that tree longevity is a key trait for global syntheses of life history strategies, especially in connection with disturbance regimes and their possible future modifications. In addition, we challenge the long-held notion that shade-tolerant, late-successional species have longer lifespans than early-successional species by pointing out that tree species with extreme longevity do not fit this paradigm. Identifying extremely old trees is therefore the groundwork not only for protecting and/or restoring entire landscapes, but also to revisit and update classic ecological theories that shape our understanding of environmental change.
資料來源:
https://nph.onlinelibrary.wiley.com/doi/10.1111/nph.17148
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