EU forest harvesting “surge” based on incorrect figures

The JRC study, published in a paper entitled “Abrupt increase in harvested forest area over Europe after 2015” and published on July 1, 2020, in the journal Nature found that the total area of forests ‘clear-cut’ harvested in the EU in 2016-2018 was 49 percent higher than in 2011-2015.

Overall, the “gap in forest cover created by cutting operations” increased by 34 percent in 2016-2018 compared to 2011-2015 across the EU, according to a statement.

Furthermore, that the 2016-2018 EU forest harvested area and biomass removal was located in seven EU countries: Sweden (29 percent), Finland (22 percent), Poland (9 percent), France (6 percent), Latvia (4 percent), Germany (4 percent) and Spain (4 percent).

The authors also note that further analyses of the causes that have been driving the increased harvest will be necessary.

Harvested area decreased, removals volume increased

However, according to the Swedish Forest Agency, this dramatic increase in forest harvesting as portrayed in the article is inconsistent with Sweden’s national statistics. On the contrary, statistics from the Swedish Forest Agency and the Swedish University of Agricultural Sciences (SLU) show that the harvested forest area in Sweden has actually decreased within the studied time period, not increased by 29 percent.

When we compare the period 2011-2015 with 2016-2018, we calculate that the area harvested annually has decreased by approximately 8 percent, said Jonas Fridman, Head of Programme of the Swedish National Forest Inventory at the Swedish University of Agricultural Sciences (SLU).

According to the Swedish National Forest Inventory, a survey conducted in the field with objective statistical methods, the area of harvested forest in Sweden has been around 200 000 hectares per year during the past decade, while the volume of harvested wood has increased steadily during the same period.

Both the volume of harvested wood and Swedish wood consumption has increased by 4 percent on average annually, comparing the period 2011-2015 with 2016-2018. This is far from the dramatic increase reported in Nature, said Jonas Paulsson, a statistician at the Swedish Forest Agency.

Several methodology issues

The JRC study, conducted by JSC Ispra in Italy, makes use of a combination of high-resolution satellite records and cloud-computing infrastructures capable of handling big data. The authors note that these technologies support forest monitoring that is “independent of official statistics” and overcomes some of the limitations of national inventories.

In particular, the EU’s Copernicus earth observation programme provides a unique European monitoring capacity. European Copernicus Sentinels missions are interoperable with the NASA Landsat satellite. They provide high-resolution imagery under “free, full and open” licenses, further increasing data availability for monitoring forest management.

According to Professor Håkan Olsson, the article authors have used global maps of harvested forests, which have been compiled through analysis of satellite images by the Global Land Analysis and Discovery group at the University of Maryland (UMD GLAD) in the United States (US).

Both the satellite images and the methods used to analyse them have improved over the years, which means that more harvested forests are identified in the images in the latter years of this data set. I have had confirmation from researchers at UMD GLAD that this data cannot be used in the way JRC Ispra has used it, said Håkan Olsson, Professor in Forest Remote Sensing at the Swedish University of Agricultural Sciences (SLU).

The article contains other issues, such as attempts to disregard the effects of certain types of forest damage but not others.