Numerous buildings, including both public spaces and housing projects, are currently being constructed to accommodate a growing population expected to reach a peak of 10 billion by 2080. When you think of “buildings,” you probably associate the term with “concrete.” However, the production of concrete, which relies on cement, is highly polluting and depletes the world’s sand reserves.
As a result, there’s a need for alternative building materials, and manufacturers are already exploring several options. These include masonry bricks, plastic hooks for structural support, and cement made from shells. However, one promising solution may be the use of wood. In fact, wood, which has been used for construction for millennia, is making a comeback.
Through various experiments and techniques, this traditional building material is being reimagined with improved properties. Recently, researchers at the University of Maryland have produced a type of wood that not only pollutes less than concrete but also helps trap atmospheric CO₂.
The key to this innovation is that this wood being transgenic, which means it’s been genetically modified to enhance its properties.
Back to Wood
The use of wood as an alternative to concrete has gained traction in recent years. By 2022, the U.S. had constructed a 284-foot building using timber columns. Specifically, constructors used cross-laminated timber columns and glue-laminated beams. This approach has many advantages, including a 25% reduction in construction time. Additionally, about half of the structure is left open and can serve as both a facade and interior decoration.
Wood also offers better insulation against cold and heat and is more sustainable than concrete. Following this example, Switzerland aimed to set a height record with a nearly 330-foot wooden skyscraper.
Moreover, ongoing research is focused on enhancing wood’s strength to match steel alloys and developing transparent woods that could serve as natural insulators and reduce costs for buildings with large windows. However, it seems that wood’s potential still hasn’t been fully realized.
Most recently, researchers at the University of Cambridge discovered that certain trees are highly effective at trapping atmospheric carbon. They found that the tulip tree (Liriodendron tulipifera) and Chinese tulip tree (Liriodendron chinense) were ideal for sequestering carbon due to their internal structure. This research work highlights the importance of these trees for activities such as replanting forests or creating CO₂ traps in urban areas.
Moreover, a team of researchers at the University of Maryland, led by Yiping Qi and Liangbing Hu, has developed a type of wood that is 1.5 times stronger than natural, untreated wood. By genetically modifying poplar, they’ve produced high-performance wood that doesn’t require chemicals or energy-intensive processing to achieve greater density and improved properties compared to standard poplar wood.
By using a technique for modifying the 4CL1 gene in poplar trees, the researchers managed to create a wood had 12.8% less lignin. Lignin is a compound that must be removed by chemicals if the wood is to be optimal for construction. This polymer also helps stabilize the structure of plant cell walls to improve water and nutrient transport.
In other words, by eliminating lignin during the growth of the tree to obtain optimal wood for construction, researchers avoided producing the contamination associated with the chemicals used in the wood conditioning process. But this isn’t the only advantage. Analyses showed that this wood was denser and more resistant to traction than aluminum (specifically, alloy 6061, which is widely used in construction).
Interestingly, the transgenic poplars matured alongside other non-genetically modified poplars for six months in the greenhouse. At no time did they show any differences in structure or growth rates. As such, the new transgenic poplar wood is not only better than the natural variant, but because it doesn’t need to be treated with chemicals to remove lignin, there’s less pollution in the process.
According to Qi, the professor from the University of Maryland, the next step is to investigate whether they can achieve similar results in other types of trees.
In any case, the idea of future cities built with wood is becoming increasingly popular. Given our current scientific knowledge, wood is a very interesting material to help achieve decarbonization goals. Naturally, they’ll need to use very different type than the wood used in ancient times, or else we might be in trouble.
Image | NinaRundsveen
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