Ecological Significance of Large Old Trees

Large old trees serve as structural and functional keystones in forested ecosystems worldwide. By virtue of their stature and biomass, they disproportionately contribute to carbon sequestration and long‐term storage, regulate microclimates, stabilise soils and modulate hydrological cycles. Their hollow trunks and complex bark architecture harbour specialist invertebrates, lichens and fungi, while cavities provide nesting sites for birds and mammals. The longevity of these organisms relies on a suite of life-history traits—modular growth, hydraulic resilience and tolerance of low growth rates—that confer resistance to disturbance and environmental stress. Accelerated juvenile growth under elevated resource availability can shorten lifespan, leading to fluctuating patterns of carbon residence time. Beyond ecological functions, large old trees possess cultural, aesthetic and historical significance, yet face mounting threats from land-use change, logging and fragmentation. Conservation and sustainable management of these trees underpin efforts in biodiversity maintenance, climate change mitigation and the preservation of ecosystem services.

Research from Nature Portfolio

Recent analyses of global tree-ring databases have revealed a near-universal trade-off between growth rate and lifespan: individuals exhibiting rapid juvenile growth often experience reduced longevity. Simulation models informed by these empirical findings indicate that enhanced growth—driven by elevated atmospheric CO₂ or warming—may initially bolster forest carbon uptake but will likely be offset by increased canopy mortality over decadal timescales, thereby neutralising net carbon gains. Complementary studies employing dendrochronological chronologies from millennia-old conifers demonstrate that faster stem productivity correlates with shorter maximum ages, implying that climate-induced growth stimulation could diminish overall carbon residence time in temperate and montane forests.

Ecological Significance of Large Old Trees publication trend

The graph below shows the total number of articles in ecological significance of large old trees across all publications each year (not limited to Nature Index journals).

Technical terms

Keystone organism: A species whose presence and role within an ecosystem have a disproportionately large effect on other organisms and ecosystem processes.

Carbon residence time: The average duration that carbon remains stored in a particular pool, such as woody biomass, before being released back to the atmosphere.

Growth-lifespan trade-off: The inverse relationship between the rate of biomass accumulation in early life stages and the eventual lifespan of the individual.

Dendrochronology: The scientific method of dating tree rings to study patterns of growth, climate interactions and historical disturbance events.

References

1. Forest carbon sink neutralized by pervasive growth-lifespan trade-offs. Nature Communications (2020).
2. On tree longevity. New Phytologist (2021).
3. Old growth forests and large old trees as critical organisms connecting ecosystems and human health. A review. Environmental Chemistry Letters (2022).
4. The Ancient Tree Inventory: a summary of the results of a 15 year citizen science project recording ancient, veteran and notable trees across the UK. Biodiversity and Conservation (2020).
5. The role of monumental trees for the preservation of saproxylic biodiversity: re-thinking their management in cultural landscapes. Nature Conservation (2017).