Scientists invented a process that makes wood stronger than steel
When trees topple into peat bogs or riverbeds, a slow alchemy begins. Hemmed in by mud, deprived of oxygen, and nudged along by microbes, the trunks gradually darken, densify, and mineralize.
Sometimes, centuries later, they emerge as prized “ancient buried wood” that resists rot and boasts a marble-like sheen.
An international group of materials scientists recently wondered: Could that natural upgrade be coaxed to happen on the lab bench – quickly, cleanly, and at industrial scale?
The answer is BioStrong Wood, a timber strengthened with fungus and heat, whose tensile strength now outmuscles common SAE 304 stainless steel while weighing far less.
The project was a collaboration between the University of the Basque Country (EHU), Wuhan University, and the Chinese Academy of Sciences.
The outcome, the experts argue, is not merely a clever composite but a glimpse of circular, sustainable materials which could replace the non‑renewable and highly polluting materials on which our economy is based.
Why wood still matters
Humans have used wood for millennia, yet most high‑performance engineering still defaults to steel, aluminum, or petro‑derived plastics.
Wood’s natural drawbacks – porosity, moisture absorption, and inconsistency – confine its use to beams and boards, not precision-engineered parts.
However, study co-author Professor Erlantz Lizundia sees untapped potential: “Wood is one of the most accessible biological materials, but outside its conventional use, it is barely being explored for high‑performance applications.”
Taming flaws could let designers replace fossil-heavy materials with a climate-friendly, carbon-storing feedstock that grows on trees.
Wood uses fungus and geology
Nature already offers a recipe. In ancient buried wood, modest heat and pressure, along with microbial enzymes, partially break down lignin – the amorphous polymer that cements cellulose fibers.
This allows the remaining molecules to repolymerize into a tighter, hydrophobic network. The Basque-Chinese team accelerated that evolution in three deliberate steps:
- Selective fungal digestion – Planks of fast‑growing poplar and radiata pine were inoculated with white‑rot fungi. Over several days the microbes chewed specific ether bonds in lignin, loosening the microstructure while leaving the strong cellulose framework largely intact.
- Chemical tuning – A mild alkaline wash halted fungal growth and removed low‑molecular‑weight residues, setting the stage for new crosslinks.
- Hot pressing under high pressure – Boards were stacked and compressed at temperatures above 356 °F (180 °C). Cell walls collapsed, voids vanished, and fragmented lignin pieces fused into fresh carbon–carbon bonds, welding the lumber into a dense, horn-like slab.
This hybrid bio‑thermo‑mechanical route preserves up to 85 percent of the original mass – far higher than acid‑delignified “super woods” – and requires little solvent or energy beyond the press cycle.
Wood withstands extreme stress
Mechanical trials show why the researchers are excited. BioStrong Wood survives tensile stresses above 530 MPa – edging out stainless steel’s typical 520 MPa – and absorbs over eleven times more energy before fracturing than raw wood.
Flexural tests reveal a threefold jump in bending strength. Thermal cycling from –321 °F (–196 °C) to 248 °F (120 °C) hardly alters its stiffness, and water contact angles near 140° keep moisture at bay. In accelerated weathering chambers, samples showed negligible swelling or mildew.
Behind the numbers lies a reengineered microarchitecture. X‑ray diffraction indicates cellulose crystallinity rises during pressing, while scanning electron microscopy shows near‑complete elimination of pores.
Reformed lignin acts like a molecular epoxy, locking cellulose sheets together and sealing pathways for water or oxygen.
Carbon capture in every plank
Strength is only half the story; so is sustainability. Using standard life-cycle assessment protocols, the authors calculate that each 2.2 lbs of BioStrong Wood sequesters roughly 2.6 lbs of CO₂ net, even after accounting for energy, chemicals, and fungal cultivation.
The negative footprint contrasts starkly with steel (4.2 lbs CO₂ emitted per 2.2 lbs produced) or glass-fiber composites (~11 lbs CO₂ per 2.2 lbs).
Techno-economic analysis pegs potential production costs near ¥2 CNY (≈ US $0.30) per 2.2 lbs – dramatically cheaper than aerospace polymers and competitive with plywood.
“Our results show that it is possible to obtain materials with a very high mechanical performance and which are, in turn, economically viable and offer carbon capture capabilities,” noted Professor Lizundia.
Future uses for fungus wood
Early prototypes hint at diverse uses, from vehicle panels to sports equipment cores and impact-resistant phone cases.
They could also serve as exposed beams with fossil-wood aesthetics or cryogenic insulation supports due to thermal-shock resistance.
Because the process accepts multiple softwood and hardwood species, regional mills could tap local forestry residues instead of importing steel rebar or petrochemical resin.
From lab to lumberyard
Scaling will demand continuous‑press technology, rapid fungal bioreactors, and strict quality control to homogenize input lumber.
Building codes require researchers to characterize fire behavior, often a stumbling block for dense woods.
End‑of‑life recycling pathways, perhaps via controlled pyrolysis to biochar, also need definition.
The researchers are already testing other fungal strains and shorter incubation times to cut lead time from days to hours.
Wood joins the big leagues
The BioStrong Wood story demonstrates a broader shift. Engineers are revisiting biological feedstocks not just for novelty, but to replace emissions-heavy incumbents at the structural level.
Whether it is mycelium foams, bacterial cellulose films or now fungus toughened wood, the toolkit of renewable high‑performance materials including wood is expanding.
This study shows that by letting nature handle part of the chemistry, scientists can leapfrog traditional limits of wood. That opens the door to steel‑class strength without the steel‑class carbon bill.
If trials succeed, pallet-bound planks could soon top skyscrapers or rocket fairings. Even in advanced engineering, well-crafted wood can still compete with metal.
The study is published in the journal Science Advances.
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