A team of engineers has discovered a simple, affordable way to make ordinary wood much stronger—without adding extra weight or changing how it bends.
By adding tiny particles of iron called ferrihydrite to red oak, they were able to reinforce the wood at a microscopic level.
This breakthrough could lead to greener alternatives to steel and concrete in things like buildings, bridges, furniture, and flooring.
This research is part of a growing effort to create high-performance materials from natural and renewable sources, like plant waste and wood.
Wood contains a material called lignocellulose, which is found in many plants and is easy to collect and modify.
Since the world produces around 181.5 billion tons of wood each year, it’s one of the most widely available eco-friendly materials.
The study was led by researchers from Florida Atlantic University, the University of Miami, and Oak Ridge National Laboratory.
They wanted to find out whether it was possible to make wood stronger by adding very small amounts of hard minerals—without making it heavier, more expensive, or harmful to the environment.
Their focus was on a type of hardwood called “ring-porous” wood, which includes trees like oak, maple, and cherry. These trees have large vessels shaped like rings that carry water through the wood. For this study, the researchers used red oak, a common hardwood in North America.
To strengthen the wood, the team used a simple chemical process. They mixed ferric nitrate with potassium hydroxide to create ferrihydrite—an iron-based mineral often found in soil and water.
This mineral was then infused into the wood, where it settled inside the tiny cell walls.
The results were impressive. The treated wood became stronger at the cellular level, but its weight barely changed. It also remained just as flexible, which means it bends and breaks in a similar way to untreated wood. The researchers think this is because the added minerals weakened the connections between the wood cells slightly, even though they made the cell walls themselves tougher.
What makes this work stand out is that the strengthening happens inside the wood’s natural structure, without covering it in coatings or glues. Most earlier studies only looked at small sections of wood or didn’t manage to get minerals inside the cell walls. This new method worked on whole pieces of wood.
To see how the treatment worked, the team used high-tech tools. One tool, atomic force microscopy (AFM), allowed them to look at the wood on an extremely small scale—measuring properties like stiffness and flexibility. They also used a technique called AM-FM, which uses vibrations to get both detailed images and measurements of elasticity.
In addition, they used a scanning electron microscope to press tiny probes into the wood, measuring how it responded to force. They also tested how both regular and treated wood samples performed in larger bending tests.
By studying the wood from the inside out, the researchers learned exactly how the treatment improved strength without changing the wood’s behavior. According to Dr. Vivian Merk, one of the study’s authors, this kind of multi-level testing is key to designing better natural materials.
The findings were published in the journal ACS Applied Materials and Interfaces.
According to Stella Batalama, dean of the College of Engineering and Computer Science, this research is a big step forward in making construction materials that are both strong and sustainable.
It could help reduce waste, lower carbon emissions, and support greener building methods for the future.
