Europe has lost a vastly increased area of forest to harvesting in recent years, data suggests, reducing the continent’s carbon absorption capacity and possibly indicating wider problems with the EU’s attempts to combat the climate crisis.
Many of the EU’s forests – which account for about 38% of its land surface area – are managed for timber production, and thus harvested regularly. But the loss of biomass increased by 69% in the period from 2016 to 2018, compared with the period from 2011 to 2015, according to satellite data. The area of forest harvested increased by 49% in the same comparison, published in the journal Nature Research.
This indicates that much more harvesting has occurred in a short period, even accounting for natural cycles and the impact of events such as forest fires and heavy snows. The harvested area could be expected to vary by less than about 10% owing to cycles of growing and planting, and similar effects, according to Guido Ceccherini of the EU Joint Research Centre, lead author of the study.
Other factors are therefore likely to be in play, and these could include increased demand for wood as a fuel, and bigger markets for timber and other wood products. The satellite data could therefore be an early indicator of unsustainable demands being placed on the EU’s forests.
The loss of forest biomass is most pronounced in Sweden, which accounted for 29% of the increase in harvesting, and Finland, for about 22%. Much less affected were Poland, Spain, Latvia, Portugal and Estonia, which jointly accounted for about 30% of the increase in the 26 countries studied.
Ceccherini told the Guardian that the observed increase in harvesting and the loss of biomass was unlikely to result in a decline in the area of the EU that is forested overall, as most of the harvested forests would be regenerated. But it would disrupt the carbon absorption capacity of the EU’s forests in the short term, he said.
“The forests continue to remain a carbon sink, but less than before,” said Ceccherini. “Even if part of the harvested biomass carbon is used in long-lasting wood products, possibly replacing more energy-intensive materials such as steel or cement, most of it will return to the atmosphere as CO2 in a short period of time, [from] months to a few years. Until the carbon stock in harvested areas returns to previous levels, which takes several decades, depending on the type of forest, an increase in harvest is therefore equivalent to an increase in carbon dioxide emissions to the atmosphere.”
Forests offset about 10% of the EU’s greenhouse gas emissions. As the areas harvested are likely to be replanted, the new growth will continue to absorb carbon dioxide from the atmosphere, so Europe’s carbon balance may not be greatly affected in the long term.
However, the researchers said it was important to find out why the harvesting has increased so suddenly, in case it indicates wider underlying problems with the way in which Europe’s forests are being managed. This study cannot definitively establish the causes of the increases in harvesting, so more research is needed.
Increase in demand for timber and wood products, such as pulp and paper, and more burning of biomass for fuel may be behind the rapid rise in harvesting observed in the Nordic countries. If so, according to the researchers, it is important to know so that any adverse impacts can be quickly contained.
Prof Thomas Crowther, founder of Crowther Lab, who was not involved in the research, said: “It is concerning to see that the increasing demand for forest products may be reducing the carbon stored within living biomass in European forests. It is possibly more concerning that forest removal may also threaten the storage of carbon below ground. These high-latitude forests support some of the largest soil carbon stock on earth. If forest clearing threatens the integrity of high-latitude soil carbon stocks, then the climate impacts may be stronger than previously expected.”