Forests are more valuable alive than dead, at least according to the more than 670 scientists who signed a letter urging world leaders to quit burning trees for energy. The plea comes as delegates gather for the United Nations Biodiversity Conference that begins today in Montreal.

The scientists want to stop to the industrial burning of wood for electricity and heat, referred to as forest bioenergy. The practice needs to be replaced by wind and solar energy, they write, to protect forests and creatures that make a home there.

“The goal to halt and reverse the global loss of nature could fail due to the growing pressure on forests from this industry,” the letter says. It’s addressed to the heads of government of China, the US, Canada, the UK, South Korea, and Japan, as well as European Commission President Ursula von der Leyen.

Bioenergy is controversially labeled as renewable energy by governments and international institutions, including the US and EU. It’s also technically considered the world’s biggest “renewable” energy source by the International Energy Agency (IEA) because, unlike wind and solar, it’s already widely used as a heating and transport fuel.

To be considered renewable, the plants or trees used to produce bioenergy are supposed to be sustainably managed — i.e., they need to grow back. But it can take forests decades or even centuries to recover from clearcutting, the authors of the letter write. Often, forests that have been cleared are replaced with monoculture plantations, tree farms of a single species that provide nowhere near the same ecological benefits or shelter for wildlife.

Take the prothonotary warbler, a little bird with bright yellow feathers that fade to slate blue along its wings, which breeds in wooded areas in the Southeastern US. It’s one of the species “declining due to the loss and degradation of these forests” for bioenergy, the scientists write.

Hardwood forests in the Southeastern US have become one casualty of a bioenergy boom driven by countries in Europe turning to wood pellets as an alternative to coal. Bioenergy suppliers harvest forests in North Carolina and Virginia to produce wood pellets that are shipped overseas to be burned in power plants. The US exported around 5.7 million metric tons of wood pellets to the UK in 2019, the letter notes, which would have required clearing an area bigger than the UK’s 150-square mile New Forest. Beyond decimating forests, growing demand for wood pellets has also burdened Black communities in North Carolina with more pollution and noise, Scalawag Magazine reported in 2020.

The scientists who penned the new letter are worried that these kinds of problems will only balloon as bioenergy becomes more popular. Annual biofuel demand is expected to grow by nearly 30 percent by 2026, according to the IEA. It’s become even more appealing to policymakers when paired with devices that capture carbon from power plants burning wood pellets. The emerging technology is called BECCS, short for Biomass Energy with Carbon Capture and Storage. If the carbon dioxide that comes from burning the wood is captured and stored long-term, countries can fold bioenergy into their plans to tackle climate change by reaching net zero CO2 emissions.

“Troublingly, because it has wrongly been deemed “carbon neutral,” many countries are increasingly relying on forest biomass to meet net zero goals. This is harming our world’s forests when we need them most,” the letter says.

Forests naturally store carbon dioxide, a service that logging for bioenergy negates. Moreover, forests are teeming with life, which is why the scientists are making noise now during the UN Biodiversity Conference. Up to a million species face the threat of extinction by the end of the century, the scientists write, mostly from losing their habitats. One of the measures delegates are expected to debate at the conference is an agreement to protect 30 percent of Earth’s land and water by 2030.

If that’s to happen, the world also “must also commit to ending reliance on biomass energy,” the letter says. “The best thing for the climate and biodiversity is to leave forests standing.”