A groundbreaking study has revealed a unique category of wood, ‘midwood’, in the tulip tree. This potentially transforms understanding of plant biology and improves the potential for carbon capture.
The study, conducted collaboratively by researchers from the University of Cambridge and Jagiellonian University in Poland, analysed the nanoscale architecture of the tulip tree’s secondary cell walls using low-temperature scanning electron microscopy. Their findings have redefined traditional classifications of wood into hardwood (angiosperms) and softwood (gymnosperms) by suggesting a unique middle ground—labelled as ‘midwood’.
The tulip tree, also referred to as the yellow poplar, is a common sight in North America and is renowned for its rapid growth rate. Reaching heights of approximately 150 feet and growing 25 inches per year on average, this tree is not only noted for its aesthetic value but also for its practical uses in manufacturing furniture, toys, and musical instruments. More compellingly, the tulip tree is exceptionally adept at carbon capture, reportedly absorbing two to six times more carbon in forests where it is the dominant species.
The researchers set out to understand why the tulip tree is so efficient at capturing carbon. Their detailed examination revealed a unique structural feature in the tree’s wood. Angiosperms typically have macrofibrils—cellulose filaments—around 15 nanometers in diameter, while gymnosperms have macrofibrils measuring around 25 nanometers. Uniquely, the tulip tree’s macrofibrils measured somewhere in between these dimensions, hence the term ‘midwood’.
“Liriodendrons have an intermediate macrofibril structure that significantly differs from typical hardwood or softwood,” explained Jan Łyczakowski, a co-author of the study. “This structural distinction aligns with the species’ divergence from magnolia trees around 30-50 million years ago, a period marked by a rapid reduction in atmospheric CO2.” This evolutionary adaptation is hypothesised to contribute to the tulip tree’s superior carbon storage capability.
Raymond Wightman of the University of Cambridge elaborated, “Our survey data provides fresh insights into the evolutionary relationships between wood nanostructure and the cell wall composition. This pivotal differentiation in the tulip tree’s intermediate macrofibril structure could explain its superior carbon capture abilities.”
The implications of this discovery extend far beyond botanical classification. The concept of ‘midwood’ opens new avenues for carbon capture strategies. Researchers propose that by understanding the unique properties of tulip trees, it may be possible to breed similar characteristics into other species, enhancing their carbon absorption efficiency. This potential was underscored in an article by Łyczakowski and Wightman in The Conversation.
“We now recognise the necessity to reassess our categorisation of woods,” the researchers commented. They are driven to explore if other trees possess similar ‘midwood’ attributes and whether such traits can be harnessed to mitigate the effects of climate change.
As the scientific community grapples with this fresh paradigm, it’s clear that the discovery of ‘midwood’ could catalyse significant advancements in both ecological science and practical applications aimed at reducing atmospheric CO2 levels. Further research will determine the extent to which these findings can be applied to other species and whether new wood types await discovery.
