Wood biomass is a controversial renewable fuel; the European Union’s Renewable Energy Directive (RED) considers it carbon neutral, while critics say reforestation of areas takes too long to make up for carbon sink loss.

For a recent study, researchers used a model to project forest cover if wood biomass is competitively priced and forest management is intensive.

The result, according to the study, would be an increase of 1 billion hectares (2.5 billion acres) of forest by 2100, but critic says replacement tree farms are poor substitutes for existing natural forests.

The continued use of wood-derived biomass could result in a potential 30% increase in worldwide forest cover — more than a billion hectares (2.5 billion acres) — by the year 2100, according to a new research paper. The researchers say their calculations show that all that’s needed are the right incentives, higher values on products, and stricter forest management.

The outcome of the study is the idea that providing a competitive financial incentive is one factor in encouraging the reforestation of areas where wood has been cut for biomass. For instance, if wood can earn harvesters more money than a replacement crop, such as palm for oil, then they would be more inclined to replant trees or afforest other areas, thus leading to an increase, over time, of overall forest cover.

Other factors like intensive forest management can result in the faster regrowth of areas of newly planted trees.

“We calculate that for every 1% increase in timber price, the area of plantations increases by 0.32% globally,” the report said.

The European Union’s Renewable Energy Directive (RED) considers the use of wood biomass to be a carbon-neutral form of renewable energy because in theory, wood waste releases carbon as it naturally breaks down anyway, and therefore wood pellets are no more of a carbon pest.

But critics argue that whole trees end up being cut to make pellets instead, and concerns have been raised that the time it takes to replant forests used for biomass is too long, which negates an area’s ability to act as a carbon sink.

Last year, six plaintiffs from across Europe and the U.S. filed a suit against the EU, alleging that the conversion from coal- to wood-pellet burning was having a disastrous effect on the atmosphere, because newly planted trees do not grow fast enough to absorb carbon.

The new study comes just months after the COP25 climate summit in December, when Michael Norton, the program director of the European Academies’ Science Advisory Council (EASAC), warned against “waiting for new trees to grow while pumping additional carbon into the atmosphere by burning trees for energy.”

At the same summit, Will Gardiner, the CEO of wood pellet firm Drax, insisted that “a managed forest that keeps growing continues to capture more carbon.”

Speaking to Mongabay by phone, Adam Daigneault, one of the study’s co-authors and an assistant professor of forest, conservation and recreation policy at the University of Maine, stressed that the study was “not saying that this is a perfect cure all, because if you’re killing all incentives to have biomass removed … you actually get more forest loss.”

“Yes, it’s not perfect, but you’re at least retaining some forest as forest that might not otherwise be there,” he added.

Daigneault said it’s important to note that increased demand for biomass would not reduce logging; “It will go up,” he said. However, in the long run, the adjustment of prices for timber for biomass could mean that “the land is worth more as trees than something else.”

A statement from the University of Maine that accompanied the release of the report said the researchers used a global timber model to assess and compare bioenergy demands and timber harvesting in more than 200 forests in 16 different regions.

“While policy approaches vary on the regional level, their modeling analysis of the forest carbon rental payment approach indicates that forest area will increase substantially across the globe, with medium price scenarios leading to 500 million to 700 million new hectares of forests,” the statement said.

Asked if the billion-hectare projection was reasonable, Daigneault said it was achievable because “the model assumes that you have proper institutions … and proper knowledge” of forest management.

He pointed to South America as one region where he has anecdotally observed an increase in monoculture tree plantations, and said that, globally, the number of new tree plantations has “doubled” over the past 30 years.

“Incentivizing both wood-based bioenergy and forest sequestration could increase carbon sequestration and conserve natural forests simultaneously,” the researchers said in the abstract of the report. “We conclude that the expanded use of wood for bioenergy will result in net carbon benefits, but an efficient policy also needs to regulate forest carbon sequestration.”

The report does say, however, that while higher timber prices can incentivize afforestation, they also “encourage harvesting of natural forest areas.” In addition, the model only projects an increase in total carbon sequestration when the demand for woody biomass exceeds 1.1 billion cubic meters per year by the year 2100.

Mary Booth, an ecosystem scientist and the director of the nonprofit Partnership for Policy Integrity, described the study as a “disaster” that is being spun “as a positive story.”

“Every one of their scenarios shows a massive loss in natural forest area relative to the baseline,” Booth said in reference to the report’s graph projections. “They are projecting up to 250-million hectare loss in natural forests; whereas natural forests are the best defense against climate change. They are proposing that we should just tear them all up and replace them with plantations.”

In reality, she told Mongabay in an interview, replacement plantations are poor substitutes for the existing carbon sinks — both above and below ground — in natural forests, and “you would completely lose the ecosystems” in them, too.

“I say that if you want to start saving carbon right away, [natural forests] are already doing an amazing job soaking up carbon,” Booth said.

Booth, who advised the plaintiffs in the biomass case against the EU, pointed to Latvia and Slovakia as countries where incentivized wood bioenergy policies have resulted in massive carbon storage losses. In the U.S., she said, similar losses have also been reported in southern forests, where “what we see is a loss in carbon.”

Banner image: Rainforest in Bukit Tigapuluh in Indonesia. Photo by Rhett A. Butler.

Citation:

Favero, A., Daigneault, A., & Sohngen, B. (2020). Forests: Carbon sequestration, biomass energy, or both? Science Advances, 6(13), eaay6792. doi:10.1126/sciadv.aay6792