WEST VIRGINIA UNIVERSITY
PICTURE: WVU ALUMNUS JUSTIN MATHIAS HOLDS A TREE EXTRACTION DRILL TO EXTRACT TREE KINGS AT GAUDINEER KNOB, WEST VIRGINIA. MATHIAS AND RICHARD THOMAS, PROFESSOR OF FOREST ECOLOGY AND CLIMATE CHANGE,… show more CREDIT: WESTVIRGINIA UNIVERSITY
New research by biologists at West Virginia University shows trees around the world are using more carbon dioxide than previously reported, making forests even more important in regulating the Earth’s atmosphere and forever changing our attitudes towards climate change.
In a study published in the Proceedings of the National Academy of Sciences, Professor Richard Thomas and alumnus Justin Mathias (BS Biology, ’13 and Ph.D. Biology, ’20) synthesized published tree ring studies. They found that the increase in carbon dioxide in the atmosphere over the past century has led to an increase in trees’ water-use efficiency, the ratio of carbon dioxide absorbed through photosynthesis to water lost through transpiration – the act of “breathing out” “Water vapor from trees.
“This study really highlights the role of forests and their ecosystems in climate change,” said Thomas, interim associate provost for graduate academic affairs. “We see forests as ecosystem services. These services can be many different things – recreation, wood, industrial. We show how forests perform another important service: as sinks for carbon dioxide. Our research shows that forests around the world use up large amounts of carbon dioxide. Without that, more carbon dioxide would be released into the air and accumulate in the atmosphere even more than it already is, which could exacerbate climate change. Our work shows another important reason to preserve, maintain and keep our forests healthy. “
Previously, scientists thought that in the last century trees used water more efficiently due to decreased stomatal conductivity – which means that trees hold back more moisture if the pores on their leaves close slightly as carbon dioxide increases.
However, after analyzing using carbon and oxygen isotopes in tree rings from 1901 to 2015 of 36 tree species in 84 locations around the world, the researchers found that in 83% of cases, the main driver of trees’ increased water efficiency was increased photosynthesis – You processed more carbon dioxide. In the meantime, the stomatal conductivity only led to an increase in efficiency in 17% of the cases. This reflects a major change in the explanation of the water efficiency of trees in contrast to previous research.
“We have shown that photosynthesis has actually been the overwhelming driver behind increasing the efficiency of tree water use over the past century. This is a surprising finding as it contradicts many previous studies,” said Mathias. “At a global level, this will potentially have a major impact on the carbon cycle as more carbon is transferred from the atmosphere to trees.”
Since 1901, the intrinsic water use efficiency of trees has increased by about 40% globally, while atmospheric carbon dioxide has increased by about 34%. Both traits have increased about four times faster since the 1960s compared to previous years.
While these results show that the increase in carbon dioxide is the main factor behind the more efficient use of water by trees, the results also vary depending on temperature, rainfall and drought of the atmosphere. These data can help refine models that can be used to predict the effects of climate change on global carbon and water cycles.
“An accurate representation of these processes is crucial for well-founded predictions about what could happen in the future,” said Mathias. “This helps us make these predictions a little less uncertain.”
The study is a product of seven years of research collaboration between the researchers during Mathias’ time as a doctoral student. After graduating from WVU, Mathias moved to the University of California in Santa Barbara as a postdoctoral fellow.
“Since moving to California, my job has shifted away from working in the field, collecting measurements, analyzing data, and writing manuscripts,” Mathias said. “My new position is more focused on ecological theory and ecosystem modeling. Instead of measuring plants, I hypothesize and find answers to questions using computer models and math. “
In the future, Mathias aims to become a professor at a research university in order to continue these research activities.
“I would like to run my own laboratory at a university, supervise PhD students, and pursue research questions in order to build on the work already done. Great progress has been made in our field. There are also an infinite number of questions that are relevant for the future, ”said Mathias. “I owe everything to my time and training from the people at WVU. My long-term goal is to be in a position where I can advance the field and give something back by teaching and mentoring students. “