Keith Reinhardt and student inspecting saplings.Madeleine Coles

News Editor

Keith Reinhardt, an Assistant Professor of Biological Sciences at ISU, wanted to understand why trees die. More specifically, he wanted to understand the phenomenon of whole forest mortality- when an entire forest dies off in instances of drought, even in typically cold, wet places.

“I did some studies with some pines that are native to our area, and I subjected them to severe drought,” Reinhardt said.

He suspected that the trees might possibly be dying because they close their stomata in times of severe drought in order to prevent water from escaping. However, this also prevents the plants from taking in any carbon dioxide to convert into food.

Additionally, when plants keep their stomata closed for extended periods of time, it renders the plants unable to move water around to transport nutrients and keep their cells well-watered, something also known as hydraulic dysfunction.

Reinhardt wanted to know if the plants were dying from starvation or hydraulic dysfunction, and he wasn’t the only one who wanted to know.

Henry Adams, a professor at Oklahoma State University, planned to combine data from Reinhardt’s experiments as well as the experiments of over 60 other scientists to determine if that would lead to any more information being revealed about the death of the trees.

The findings from Reinhardt’s experiment supported that the plants were being killed by hydraulic dysfunction rather than the lack of carbohydrate reserves, a result that was supported by the other studies within the paper.

“Hydraulic failure seemed to be a universal finding that was associated with mortality,” Reinhardt said. “If [plants] lost more than 50% of their hydraulic conductivity, almost universally there was mortality. From this large, global data set, it seems that it’s mostly due to problems with the storage and transport of water and less to do with problems with carbohydrates.”

According to Reinhardt the findings from these studies can be used for predictive power.

“We know that climate is changing,” he said. “We know that we did not used to have this phenomenon of whole forests dying off. So when we’re trying to predict what atmospheric concentrations of carbon dioxide are going to look like in the future, but also where forests are going to be and what crops are going to be able to be planted in certain areas, we need to know this fundamental information.”

The paper was published in the journal Nature Ecology and Evolution and received national attention from multiple scientific outlets, which Reinhardt said was good for the study and for ISU.

“It shows the world that Idaho State University is performing strong research, and [our] facilities, faculty and students are on par with leading institutions around the world,” Reinhardt said.

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