Study

Limits to tree growth and longevity

Munné-Bosch, S.

Trends in Plant Science, 2018

Peer-reviewednarrative reviewnot applicable

What they did

A review of the evidence for and against physiological ageing in long-lived trees, covering meristem function, hydraulic architecture, mutation accumulation and the ways an old tree actually dies.

Studied in: Tracheophyta

Trees do show age-related changes — reduced shoot growth, greater hydraulic resistance with height, accumulated damage — but there is no clear evidence of an intrinsic programme that ends a tree at a set age. Death in old trees is generally attributable to an external event acting on a weakened structure.

What it means

The authors' reading, and ours. Where they differ, that difference is the point.

How the authors put it

Tree longevity is limited by accumulating physiological and mechanical constraints rather than by a determined lifespan, and whether trees senesce in the strict sense remains open.

How NatureHQ reads it

The right answer to "can a tree die of old age" is that the question needs restating first. A tree is modular: it grows from meristems that stay embryonic, it can lose most of itself and continue, and it can wall off damage rather than heal it. Nothing there sets a clock. What accumulates is height, mechanical load, hydraulic difficulty and injury — so old trees become easier to kill without there being an age at which they stop.

Limitations

A review; it weighs existing evidence rather than testing between the competing explanations.
Very old trees are rare and hard to sample, so much of the evidence is from few individuals.
Distinguishing intrinsic senescence from accumulated external damage is difficult in principle, not only in practice.