Cut logs in Sweden
Arterra/Universal Images Group
There has been a large increase in the number of trees felled and removed from European forests. Satellite images suggest that the forest area harvested each year between 2016 and 2018 was 49 per cent higher than the area harvested each year between 2011 and 2015.
Grégory Duveiller at the European Commission Joint Research Centre in Italy and his colleagues analysed satellite data that measured the amount of forest cover and area of trees cut between 2004 and 2018 across 26 European Union countries.
The satellite imagery came from the Global Forest Change database, which includes all vegetation greater than five metres high.
The team combined the satellite data with estimates of forest biomass to quantify the amount of wood harvested. “From above, you see forest and non-forest,” says Duveiller. “You don’t see how tall the (harvested) trees are.”
According to the researchers’ estimates, between 2016 and 2018, the annual levels of harvested forest biomass were 69 per cent higher than in the preceding five years.
A rise in tree removal was particularly marked in Sweden and Finland, which accounted for more than half of the total observed increase in harvested area. These countries have historically large forestry-related industries, and also have areas of forest used for fuel production that have reached harvest maturity, says Duveiller.
Another possible explanation for the surge in harvesting is an increase in demand for wood-based products. “There are several drivers that are possible but a causal connection is difficult to prove and quantify,” says Duveiller.
“We cannot really jump to conclusions directly about implications for greenhouse gases right now,” says Duveiller, because forests in Europe are also expanding. It is currently difficult to quantify the rate of that growth to determine whether it offsets the losses from harvesting, he says.
If the harvesting continues at similar rates, the team suggests that in order to reach climate neutrality by 2050, additional emissions reductions in other areas would be needed to compensate for the carbon losses from forests.
Journal reference: Nature, DOI: 10.1038/s41586-020-2438-y
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