California plans to use forest thinning to reduce wildfire risk. New research suggests the state could also see a climate benefit by repurposing waste wood produced by thinning.
By Andrew Chapman | https://eos.org | 5 January 2022
Wildfire risk reduction in California is a climate conundrum.
In early 2021, the state set a goal of reducing wildfire risk on 1 million acres (405,000 hectares) of forest per year through prescribed burning and forest thinning. However, thinning treatments lower the forest’s capacity to remove carbon dioxide from the atmosphere, and the harvested smaller, low-value trees are typically burned or left to decay, which releases even more carbon.
“There’s this unique role of emerging and innovative wood products in achieving forest management that reduces wildfire risk but also preserves forests as carbon sinks.”
In a study published early this month in the Proceedings of the National Academy of Sciences of the United States of America, researchers from the University of California, Berkeley, provide a possible path to limiting both carbon emissions and wildfires by turning the low-value wood harvested during forest thinning into new products.
“There’s this unique role of emerging and innovative wood products in achieving forest management that reduces wildfire risk but also preserves forests as carbon sinks,” said the study’s senior author, Daniel Sanchez.
Modeling Forest Management
For the analysis, Sanchez and his colleagues used forest inventory data from the U.S. Forest Service for more than 33 million acres (13.4 million hectares) of California forests and applied several forest management models to simulate the forest growth, forest treatments, wildfire risks, and revenue potential over the next 40 years.
They ran simulations of three scenarios and then estimated the carbon impacts of each scenario. Two scenarios modeled business-as-usual forest management in California with variations in how much wood is sold. The third introduced a value to the low-value wood generated from forest thinning, allowing it to be used for new products. Smaller trees can be turned into a construction-grade wood product called oriented strand board, which retains the wood as a carbon store. A mixture of forest residues, including leaves and bark, can be used to make low-carbon fuels, such as hydrogen fuel.
Benefits of Innovative Wood Products
The study found that the “innovative wood product” scenario lowered both the wildfire risk and carbon emissions from wildfires and postfire decay compared to the other two scenarios. On top of that, turning low-value wood into low-carbon fuels and wood products displaced products that are less carbon friendly, like gasoline or steel and concrete. So even though the amount of carbon stored in living trees decreased, the new wood market prevented the equivalent of as much as 16 million metric tons of carbon dioxide per year from entering the atmosphere when compared to the other two scenarios. The researchers estimated that the climate benefit could be improved even further with state incentives to build affordable housing with innovative wood products.
“I think that [this paper] does point in the direction where there are real opportunities for California.”
“We find that in these innovative wood product scenarios, we do reduce the amount of net carbon. Then by putting it into products, we get all these other benefits,” said Sanchez. Another benefit is that the new wood products market could generate enough money to treat 12 million acres (4.9 million hectares) of additional forest over the next 40 years.
“It’s a really interesting paper,” said Chris Field, the director of the Stanford Woods Institute for the Environment, who has worked with Sanchez in the past but was not involved in the new study. “I think that it does point in the direction where there are real opportunities for California.”
He added that in addition to the forest and climate benefits, the innovative wood products industry could also help rural economies in California. “We’ve lost thousands of jobs in the forest products industry over the last 15 years. The industry that you would get this result from [would be] very different, but it would still be based in those communities.”
Can California Make It Happen?
Sanchez acknowledges that unforeseen challenges could arise from variables they didn’t include in the simulations. For example, the models did not predict the potential impacts on forest soils or belowground forest biomass and economic considerations such as the impact of biofuel prices on the demand for petroleum products. “There are second- and third- and fourth-order effects that we probably don’t count,” Sanchez said.
Field sees potential issues getting forest sector professionals and conservationists on the same page to move forest management toward innovative wood products. “I think it’s a direction that we can go, but it’s not entirely straightforward,” he said.
But the markets for fuel and wood products are already large in California, Sanchez said, and several existing state policies incentivize industries to use products that are more climate friendly, which might make these wood products enticing. Sanchez is eager to determine which technologies have viable business opportunities.
“I think that in a lot of ways, this provides the motivation for what people are going to have to do within California, which is not only ramp up things on the forest management side but also ramp up things on the wood products infrastructure side to get this done,” said Sanchez.
—Andrew Chapman (@Andrew7Chapman), Science Writer