Fossil fuels—coal, oil, and natural gas—come from ancient deposits formed millions of years ago beneath the Earth’s surface. These deposits are not being replenished. When these nonrenewable fuels are burned, greenhouse gases—including carbon dioxide (CO2)—are released into the Earth’s atmosphere, where they trap heat and contribute to global climate change.
Burning wood also releases CO2 and greenhouse gases into the atmosphere, but living trees are constantly removing carbon from the atmosphere and storing it in their trunks, stems and roots. As long as we’re planting and growing as many or more trees than we’re burning, using woody biomass for energy can be considered carbon neutral. (Read a study about the carbon neutrality of biopower by the Congressional Research Service.)
In reality, there will still be CO2 emissions from the machines used to harvest, process, and transport biomass feedstock, but these can be kept relatively low. The Southern Research Station (SRS) Forest Operations Research unit conducts research that helps landowners cut both the emissions and costs of biomass harvest and removal by evaluating machines and processes for efficiency and sustainability.
Another advantage of using biomass as fuel is the reduction in air pollution from sulfur and nitrous oxides that result from burning fossil fuels. Wood has less than 50 percent the nitrogen content of coal, and the sulfur content is negligible.
Using thinnings from forests for bioenergy could help reduce the “megafires” of the last few years, which release massive amounts of CO2 into the atmosphere, affect air quality globally and contribute to climate change. Using forest residues and thinnings for fuel also prevents that wood from being burned in open air slash piles with no pollution controls.
Using urban wood waste that usually ends up in landfills also reduces the amount of methane released into the atmosphere.
Growing trees for bioenergy feedstock provides additional incentive for landowners to keep their land in forests. Deforestation from land conversion contributes to global climate change by reducing the number of trees available to absorb and store CO2.