The scale and rigor of the study are what make the result so difficult to dismiss. The researchers sampled tree rings from seven widely planted conifer species, including lodgepole pine, slash pine, ponderosa pine, radiata pine, Scots pine, European larch and Douglas-fir, comparing stands in their native North American and European ranges with plantations and even self-sown invasions in Argentina, Chile, New Zealand and South Africa. By measuring basal area increment, the cross-sectional area of wood added each year, and by calculating well-established drought metrics such as resistance, recovery and overall resilience indices, the team could compare growth trajectories and drought responses under a common analytical framework. Crucially, they controlled for tree age, competition and stand history, ruling out the simplest explanations, such as younger trees or less crowded plantations, for the extraordinary performance of the Southern Hemisphere stands.

The growth gap is not subtle. In the first decades of life, conifers in non-native Southern Hemisphere plantations accumulated wood at rates far exceeding those of conspecifics in their native ranges, with the study reporting growth up to four times faster. Even when the analysis was restricted to trees of comparable age, between thirty and fifty years old, the Southern Hemisphere trees maintained markedly higher basal area increments. Native angiosperm species growing adjacent to the conifer plantations did not show the same advantage, which suggests that the effect is not simply a matter of benign Southern Hemisphere climates. Something about the conifers themselves, or about their interaction with the new environments, is driving the difference.

The physiological evidence points to a coherent mechanism: higher net carbon assimilation. Trees in the non-native ranges carried higher concentrations of non-structural carbohydrates, the sugars and starches that fuel growth and buffer trees against stress, and their wood showed lower carbon isotope ratios, expressed as δ13C values. Carbon isotope discrimination in plant tissue is governed largely by how far stomata open during photosynthesis; lower δ13C values indicate that the trees kept their stomata open more freely, imposing less limitation on carbon uptake even at the cost of greater water loss. Together with the elevated stem growth rates, these measurements paint a picture of trees that are, in effect, running their carbon economy at a higher gear in the Southern Hemisphere, assimilating more carbon, storing more of it in soluble form, and thereby entering drought episodes with fuller reserves.

That combination is what ecologists find so paradoxical. Classical ecological theory holds that plants face a fundamental trade-off: fast growth comes at the expense of stress tolerance, because resources allocated to rapid wood production cannot simultaneously be banked as storage or invested in drought defenses. The Southern Hemisphere conifers appear to escape this trade-off, growing quickly and still resisting and recovering from drought better than their native-range counterparts. The authors argue that this paradoxical pairing demands a rethink of how eco-evolutionary history is woven into ecological theory, since a species’ response to abiotic stress evidently depends not just on its genes and its climate, but on the specific historical and biotic context in which it is growing.

Several candidate mechanisms could explain the transcontinental advantage, and the study’s framing draws on ideas from invasion ecology. One long-standing hypothesis is enemy release: when a species is moved to a new continent, it leaves behind many of the specialized herbivores and pathogens that chewed away at its carbon budget at home. Recent work by some of the same authors has shown that introduced lodgepole pines host distinct foliar fungal communities in their new ranges, consistent with context-dependent pathogen release. Freed from chronic biotic attack, trees could afford both faster growth and larger carbohydrate reserves. Other hypotheses invoke evolutionary shifts, since rapid evolution in introduced populations has been shown to alter trade-offs between herbivore resistance and abiotic stress tolerance, as well as differences in soil communities, nitrogen availability and mycorrhizal partners between hemispheres.

The drought findings carry particular weight at a moment when drought-induced conifer mortality has become one of the most visible fingerprints of climate change on the world’s forests. Across the American West, the Mediterranean basin and other Northern Hemisphere regions, hotter and longer droughts have repeatedly pushed native conifer stands past their physiological limits, with low growth resilience after drought now recognized as a reliable predictor of subsequent tree death. Yet, as the authors note, conifers planted at massive scales in the Southern Hemisphere do not appear to exhibit the same magnitude of growth decline or mortality as in their native ranges. The new data confirm that this is not an artifact of observation: the introduced populations genuinely respond differently to abiotic stress, holding higher carbohydrate reserves and suffering less stomatal constraint during dry spells.

The implications ripple outward into one of the most consequential debates in climate policy: the role of afforestation and plantation forestry as global carbon sinks. Young and rapidly growing forests are among the most effective terrestrial carbon removers, and large-scale tree planting features prominently in many national mitigation pledges. If Northern Hemisphere conifer species reliably assimilate more carbon and withstand drought better in Southern Hemisphere settings, the carbon accounting of plantation forestry looks very different depending on where the trees stand. But the same biology that makes these plantations productive also makes the species formidable invaders, and introduced pines have spread aggressively into treeless grasslands and shrublands in Patagonia, New Zealand and South Africa, reducing native species richness and altering ecosystem properties. The study’s authors and other researchers caution that afforestation plans must weigh carbon gains against biodiversity costs and socio-economic impacts, which in regions such as Chile have included documented tensions between plantation expansion and local communities.

There is also a deeper scientific lesson. The result echoes an earlier finding by Callaway and colleagues that exotic invasive plants increase primary productivity in their new ranges but not at home, and a global meta-analysis showing that non-native animals are less sensitive than natives to extreme weather. Together, these studies suggest that a population’s history, the enemies it has escaped, the environments its ancestors survived, the genetic bottlenecks and founder effects it passed through, can reconfigure its physiological relationship with climate in ways that no species-level trait database currently captures. For models that forecast forest carbon storage and mortality risk under future climates, that is a humbling realization: the same species, in the same climate envelope, may not be the same plant.

What remains to be resolved is which mechanism dominates. Disentangling enemy release from rapid evolution, soil biota and founder genetics will require common-garden experiments and reciprocal transplants that the authors and their collaborators are well positioned to pursue. In the meantime, the image of a lodgepole pine in Patagonian steppe or a Douglas-fir on a New Zealand hillside, outgrowing and outlasting its cousins in Montana or British Columbia, stands as a vivid reminder that ecology’s cleanest generalizations bend when species cross hemispheres. For the millions of hectares of Southern Hemisphere plantations, and for the carbon they lock away, the finding is good news with an asterisk: the trees are thriving, but the very vigor that makes them valuable sinks is the same vigor that makes them difficult neighbors for the ecosystems they were brought to.

Subject of Research: Comparative growth and drought resilience of Northern Hemisphere conifer species planted in their native versus Southern Hemisphere non-native ranges

Article Title: Pines grow faster and are more drought resilient in the Southern Hemisphere

Article References: Fajardo, A., Gazol, A., Camarero, J. J., Gundale, M. J., Piper, F. I., Brewer, J. S., Buxton, R., Cieraad, E., Dezzotti, A., Fernández-Cortés, A., Goedecke, F., González de Andrés, E., Kritzinger-Klopper, S., Laurén, A., Llancabure, J. C., McIntosh, A. C. S., Milani, T., Moyano, J., Núñez, M. A., … Callaway, R. M. (2026). Pines grow faster and are more drought resilient in the Southern Hemisphere. Nature, 657(8132), 697-702. https://doi.org/10.1038/s41586-026-10969-8

Image Credits: AI Generated

DOI: 10.1038/s41586-026-10969-8

Keywords: conifers, pines, drought resilience, dendrochronology, plantation forestry, invasion ecology, non-structural carbohydrates, carbon isotope discrimination, afforestation, forest carbon sink, enemy release hypothesis, Southern Hemisphere