How a plant's family tree decides its carbon appetite

On 14 July 2026, a team of researchers reported a finding that recasts how plants budget their carbon. Across roughly 1,700 species spanning every continent except Antarctica, the mix of stored sugars inside a leaf or stem correlates less with the climate a plant lives in than with the family it belongs to. Some lineages stash away huge reserves; others live hand to mouth, spending carbon almost as fast as they fix it.

The study, published in Nature Ecology & Evolution and summarised on Phys.org, is the largest cross-species comparison of plant carbohydrate storage to date. Its core claim is uncomfortable for a generation of climate models: predicting how much carbon a forest will hold during a drought, a heatwave, or a wet season requires knowing the evolutionary pedigree of the trees in it, not just the temperature and rainfall outside.

Two kinds of sugar, two kinds of risk

Plants manufacture two broad classes of carbohydrate. The first, structural carbohydrates, become cell walls, lignin, and the woody tissue that holds a tree upright. These are long-term investments; they cannot easily be re-mobilised when the plant is stressed. The second class, non-structural carbohydrates (NSCs), are the plant's liquid assets. They are stored in stems, roots, and leaves as starches and soluble sugars, ready to fund new growth, repair damage, or survive a season of bad weather.

NSCs are what ecologists mean when they talk about a plant's "carbon reserve." A well-stocked tree can lose its leaves, take a beating from frost, or sit through a multi-year drought without dying. A tree that runs its reserves down to near zero is one heatwave away from mortality. The new study treats NSCs as a trait, in the same way leaf shape or wood density is a trait, and asks: which species carry a big buffer, and which do not?

What the data show

The analysis pulls together NSC measurements for 1,692 vascular plant species from 122 published datasets. Each species was scored for the concentration of soluble sugars and starches in its tissues and assigned to a major plant lineage, from ferns and gymnosperms to the sprawling angiosperm families that dominate modern vegetation.

The headline result, according to the Phys.org summary of the paper: evolutionary history explains a substantial share of the variation in NSC storage, often more than climate variables do. Some lineages, including many ferns and certain gymnosperm groups, sit at the high-storage end of the spectrum. Others, including large parts of the grass family, store comparatively little and rely on rapid growth to compensate.

The implication is that closely related species inherit a "storage strategy" from a common ancestor, much as they inherit flower shape or leaf venation. Two trees growing in the same forest under identical rainfall can differ in NSC concentration by a factor of two or more simply because their families diverged tens of millions of years ago.

Why climate models have it half-wrong

Most vegetation models used in IPCC-class assessments treat carbon storage as an emergent property of climate and soil. A warmer, wetter forest stores more carbon; a drier one stores less. The new result does not overturn that picture, but it limits it. If storage strategy is inherited, then a swap of one species for another, through forestry choice, fire regime, invasive species, or range shift under warming, can change the forest's carbon accounting in ways that climate inputs alone cannot predict.

This matters most in the dry tropics and in boreal margins, where NSCs buffer trees against exactly the extremes that climate change is intensifying. A line of pines that is evolutionarily predisposed to keep large reserves will weather a five-year drought differently from a neighbouring stand of eucalypts, even on the same soil and the same rainfall. The new framework offers a way to encode that difference into models that, until now, have largely ignored it.

There is a useful precedent in wood density, a trait that ecologists once treated as a climate proxy and now treat as a species-level predictor of drought mortality. NSC storage may be going the same way, from a residual term in a regression to a first-class variable in the models that policy depends on.

What the work does not yet say

The dataset is global but uneven. Tropical species are under-represented relative to temperate ones, and African and South American forests are sampled more thinly than European and North American ones. The Phys.org coverage does not specify how the authors weighted that imbalance, and the underlying paper's methods section will need scrutiny before the result generalises to every biome.

A second caveat: storage strategy is one piece of a larger carbon budget. A species that stores little NSC may still hold a great deal of carbon in long-lived wood, deep roots, or recalcitrant soil organic matter. Treating NSC concentration as a stand-in for total carbon storage would overstate the case. The paper's authors frame the finding as a predictor of resilience, not of standing biomass, and that distinction will matter when the result is translated into land-use advice.

Finally, the evolutionary signal the authors detect is statistical, not deterministic. Species within a lineage vary, sometimes widely. Forestry policy built on the assumption that "all gymnosperms store more" will run into the same problems that early wood-density work ran into. The result is a tool, not a verdict.

The stakes for forestry and carbon markets

If the finding holds, two practical questions follow. First, reforestation and afforestation programmes that promise carbon sequestration on the basis of species choice will need to be more careful about which species they plant where. A fast-growing species that sounds good in a brochure may also be a low-reserve species, and a single bad drought can convert a paper carbon credit into a dieback.

Second, the voluntary carbon market, which already struggles with claims about permanence and additionality, will need to incorporate lineage-level storage traits into its baseline calculations. The credibility of forest-carbon credits depends on whether the carbon stays in the trees, and storage strategy is a leading indicator of whether it will.

Neither of these policy questions is settled by a single study. But the direction is clear: predicting the carbon behaviour of a forest requires more than a thermometer and a rain gauge. It requires reading the family tree.

This piece was framed as a methodological shift in plant ecology rather than a narrow taxonomic finding. Wire coverage of the same study, including the Phys.org summary, foregrounded the species count; Monexus emphasised the modelling and carbon-market implications, where the structural consequences are larger.