Study examines carbon storage in tree roots

A recent University study found that trees store carbon differently based on the climate.

Kate Clark

A University of Minnesota study published earlier this month provides a better understanding of how trees store carbon in their roots, researchers say.

The study, partly funded by the University’s Institute on the Environment, found that carbon storage in trees’ roots differs with climate. Researchers say this information will allow for more accurate predictions of climate change’s future effects.

Estimates of aboveground biomass and carbon percentage are already fairly accurate, said forest ecology professor Peter Reich, leader of the study.

But data on roots were “crude guesses” in the past, he said, because it was impossible to measure roots without destroying the ground and the tree.

As part of the study, researchers compiled a database of 6,000 forests in 61 countries, Reich said, by combing over scientific literature published within the last 30 to 40 years.

He said in summation, the study gives researchers a “magic formula” — one that uses temperature and aboveground carbon to predict the carbon storage in roots.

Trees grow larger roots in colder climates because there are fewer nutrients and there is less water in the soil, Reich said.

Knowing the variations in belowground carbon storage can provide better projections of climate change, he said.

For example, Reich said current models for predicting the effects of climate change assume trees everywhere have similarly sized root systems.

“Knowing that they actually differ will make those models more accurate,” he said.

The study is part of the larger Plant Data Synthesis project, which works to create global databases on plant traits.

The roots study is not the only Plant Data Synthesis project that has focused on carbon processing. Another research paper recently published on coniferous trees shows that those in colder climates keep their needles longer than those in warmer climates.

The diversity in needle lifespan amazed Roy Rich, a research associate in the Department of Forest Resources and coauthor of the coniferous trees study.

The results suggest there is significant genetic diversity within coniferous tree species, he said in an email.

Rich traveled throughout Canada and northern Minnesota to sample leaves and needles about every 50 kilometers, he said.

While the Institute on the Environment has completed its funding of the Plant Data Synthesis project, Reich said research with large data collections will continue in the future.

Twenty years ago, Reich said, he and about 12 others spearheaded the notion of starting plant trait databases.

Reich was involved in an earlier dataset published about a decade ago.

“That one had data from maybe 2,500 species and maybe 10,000 records,” he said. “The ones we are working on now [contain] more than 7 million records.”

The results of the studies will help inform environmental decision-makers, said Lewis Gilbert, the Institute on the Environment’s managing director and chief operating officer.

“We can provide information to forestry services, government, and agriculture businesses on how their activities will change how forests work,” he said, “and what impact that will have on Earth and their business.”