Why do plants become woody? I am fascinated to understand the climatic drivers of evolutionary transitions towards woodiness that have occurred hundreds of times during evolutionary history.
Wood formation is a fundamental evolutionary innovation that gave rise to countless woody species. The evolutionary transition from herbaceousness towards (phylogenetically derived) woodiness is a peculiar phenomenon that dates back to Darwin's original observations. However, after about 180 years, scientists still have not figured out why plants become woody and why this has happened frequently. Therefore, I have compiled a global derived woodiness database with nearly 7000 derived woody species, showing that most of these them are native to continental regions with recurrent drought cycles. This has laid the foundation for my novel hypothesis, proposing drought as the major driver of the evolutionary transitions towards woodiness across most lineages. My team has already obtained preliminary experimental support for this hypothesis in some plant groups, but wood is a complex tissue that can probably be triggered in various ways.