A new study led by Oregon State University suggests leaves in forest canopies are not able to cool themselves below the surrounding air temperature, likely meaning trees’ ability to avoid damaging temperature increases, and to pull carbon from the atmosphere, will be compromised in a warmer, drier climate.
The findings by an international collaboration that included researchers from multiple universities and government agencies contrast with a prevailing theory in the scientific community that canopy leaves can keep their temperature within an optimal range for photosynthesis – the process through which green plants make their food from sunlight and carbon dioxide.
Published today in the Proceedings of the National Academy of Sciences, the research is important for understanding and predicting plant responses to climate change, said lead author Chris Still of the OSU College of Forestry, who notes that multiple studies suggest many of the world’s forests are approaching their thermal limit for carbon uptake.
“A hypothesis known as limited leaf homeothermy argues that through a combination of functional traits and physiological responses, leaves can keep their daytime temperature close to the best temperature for photosynthesis and below what is damaging for them,” said Still. “Specifically, leaves should cool below air temperature at higher temperatures, typically greater than 25 or 30 degrees Celsius. That theory also implies that the impact of climate warming on forests will be partially mitigated by the leaves’ cooling response.”
Read more at Oregon State University
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