Not All Carbon From Cleared Forests is Released Into Air

The volume of greenhouse gas released when a forest is cleared depends on how the trees will be used and in which part of the world the trees are grown, according to researchers at UC Davis.

The researchers published their findings in the journal "Nature Climate Change." They determined that, 30 years after a forest clearing, between 0 and 62 percent of carbon from that forest might remain in storage. "Previous models generally assumed that it was all released immediately," said lead author J. Mason Earles, a doctoral student with the UC Davis Institute of Transportation Studies.

When wood is used in wood products like flooring, that wood retains much of its carbon for decades, the researchers found. In contrast, when wood is used for bioenergy or turned into pulp for paper, nearly all of its carbon, a major contributor to greenhouse gases, is released into the atmosphere.

The researchers analyzed forest use in 169 countries. They learned that the temperate forests found in the United States, Canada and parts of Europe are cleared primarily for use in solid wood products, while the tropical forests of the Southern Hemisphere are more often cleared for use in energy and paper production.

"Carbon stored in forests outside Europe, the USA and Canada, for example, in tropical climates such as Brazil and Indonesia, will be almost entirely lost shortly after clearance," according to the study.

The study's findings could have implications for the bioenergy industry. If the United States decides to incentivize corn-based ethanol, for example, less profitable crops, such as soybeans, may shift to other countries. In turn, those countries might clear more forests to make way for the new crops, and where those countries are located and how the wood from those forests is used would affect how much carbon would be released into the atmosphere.

The study can be read here.