Structurally complex forests better at carbon sequestration

Forests in the eastern United States that are structurally complex, meaning the arrangement of vegetation is highly varied, sequester more carbon according to a new study led by researchers at Virginia Commonwealth University.

The study demonstrates for the first time that a forest’s structural complexity is a better predictor of carbon sequestration potential than tree species diversity.

“Carbon dioxide, a potent greenhouse gas, is taken up by trees through the process of photosynthesis and some of that ‘fixed’ carbon is allocated to wood,” said Chris Gough, Ph.D., corresponding author on the study and an associate professor in the Department of Biology in the College of Humanities and Sciences. “Our study shows that more complex forests are better at taking up and sequestering carbon in wood and, in doing so, they leave less carbon dioxide in the air.”

Carbon sequestration is the process by which atmospheric carbon dioxide is taken up by trees, grasses and other plants through photosynthesis and stored as carbon in soil and plant biomass, such as tree trunks, branches, foliage, and roots. Carbon sequestration in forests and wood helps offset sources of carbon dioxide to the atmosphere, such as deforestation, forest fires, and fossil-fuel emissions, according to the Forest Service of the U.S. Department of Agriculture.

Why are structurally complex forests better at carbon sequestration? Gough suggests that multiple layers of leaves may optimize how efficiently light is used to power carbon sequestration in wood.

“In other words, forests that are structurally variable and contain multiple layers of leaves outperform structurally simple forests with a single concentrated band of vegetation,” he said.

To conduct the study, the researchers used a combination of their own data, as well as data from the National Ecological Observatory Network, or NEON, which is funded by the National Science Foundation. NEON is generating long-term, publicly available data for different ecosystems in the U.S., with the aim of understanding decades-long ecological processes.

Understanding how forest structure drives carbon sequestration is important for ecologists, climate modelers, and forest managers.

“Many of the ecological indicators of forest growth and carbon sequestration fail to explicitly account for complexity,” Gough said. “We wanted to test whether more novel indicators of structural complexity are superior predictors of carbon sequestration in wood. We also wanted to know whether these predictors extend to a number of different forest types residing in various parts of the eastern half of U.S., from Florida to New Hampshire to Wisconsin.”

Source: Virginia Commonwealth University
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