By tapping nutrients from bedrock, red alder trees play a key role in healthy forest ecosystems, according to a new study.
The study published today in the journal Proceedings of the National Academy of Sciences.
Researchers from Oregon State University and the U.S. Geological Survey determined red alder, through its symbiotic relationship with nitrogen-fixing bacteria, taps nutrients that are locked in bedrock, such as calcium and phosphorus. This process accelerates rock dissolution, releasing more mineral nutrients that allow plants and trees to grow.
The study addresses the long-term implications of how nutrients make their way into ecosystems, which sustain their long-term growth and productivity and ultimately store carbon, said Julie Pett-Ridge, a geochemist in OSU’s College of Agricultural Sciences and a co-author on the study.
The research also furthers the understanding of a specific set of trees that are known for their ability to naturally fertilize forests by converting atmospheric nitrogen into forms available for other plants. This process, called nitrogen fixation, is essential for natural ecosystems.
“Nitrogen mostly comes from the atmosphere, but more than 20 other nutrients mostly come from rock,” Pett-Ridge said. “We’ve established a connection between those two processes. Nitrogen-fixing trees, which we knew were special for how they bring in nitrogen from the atmosphere, also have a unique ability to accelerate the supply of rock-derived nutrients.”