Mar 29 2018
William Schlesinger, President Emeritus of the Cary Institute of Ecosystem Studies, has reported in an Insights article published in the Science journal on March 22, 2018, that a return to firewood would prove detrimental to forests as well as the climate.
The Southern US is more intensively harvested and has far fewer forest reserves than the North and West. At the same time, the region is a hotspot for plant and animal biodiversity. (Image credit: David Allen)
While working to satisfy clean energy standards, biomass energy is often boasted as carbon neutral. To meet the energy requirements of the European Union (EU), forests in the United States (US) are transformed into wood pellets of around seven million metric tons and transported overseas annually. The electricity produced by incinerating these pellets in the EU helps to satisfy the Paris Agreement commitments.
Efforts are being made to achieve a potential increase in biomass energy in the US as it is anticipated that Congress may pronounce biomass to be carbon neutral in an attempt to rejuvenate the American forest product industry. The demand for wood pellets in the US would be further incentivized by a tax on fossil carbon.
However, there are major drawbacks in transforming forests into fuel. While taking biomass energy into account, the crucial role played by forests as a sink for carbon dioxide, which might otherwise get accumulated in the atmosphere, is ignored. Schlesinger reports that every year, approximately 31% of the carbon dioxide emitted due to human activities is stored in the forests.
When compared to plantation forests, native ones store more carbon dioxide. Fossil energy is needed to manufacture the pellets as well as to ship them overseas. Schlesinger explained that “The benefits of wood power must be discounted by the loss of the carbon sequestration that would have occurred in the original forests if they had not been harvested.”
He further added that “It makes no sense to have Europeans embracing wood pellets as carbon neutral while overlooking the carbon dioxide emitted during shipment and the losses of carbon storage from forests in the United States.”
Biodiversity must also be taken into account. In the southeastern US, wood pellets are largely produced from pine plantations. However, pines do not play a major role in preserving the rich biodiversity of the region. When there is an increase in the demand for wood pellets, they are harvested also from native forests. Innumerable species are dependent on such globally rare ecosystems.
Schlesinger concluded by saying, “Ultimately, the question is what kinds of forests are most desirable for the future. Recent research indicates that unless forests are guaranteed to regrow to carbon parity, production of wood pellets for fuel is likely to put more carbon dioxide into the atmosphere and preserve fewer species on the landscape during the next several decades.”
Following are the drawbacks of using biomass.
Fossil fuels power wood pellet export
Wood pellets harvested from plantation forests in the southern hemisphere are transported to Europe and incinerated. The amount of energy needed to carry out this shipping process can contribute to 25% of the total carbon emissions related to biomass-fueled energy generation in Europe.
Timber plantations do not store as much carbon as natural forests
Plantation forests would take about 40–100 years to store as much carbon as natural forests. Trees grown for harvesting wood pellets are normally cut within 20 years, which is inadequate time for them to ingest carbon emitted by the harvest and combustion of the earlier “generation” of natural forest.
Monoculture degrades biodiversity
In timber plantations, essentially a single tree species is predominantly grown, which cannot nurture the diversity of life characteristic to natural forests. Moreover, the increasing requirement of wood pellets increases the cost of raw wood, leading to the harvest of biologically diverse natural forests.
Cleared forests are vulnerable to non-forest development
In general, new trees are not planted in the place of forests that have been harvested for fuel. In these cases, the carbon sequestration potential of the prevalent forest is entirely destroyed.