Page 10 - Green knowledge 2022

No great increase in forest harvesting
Several forest researchers reacted when the journal Nature published very surprising figures showing a dramatic and sudden increase in forest harvesting in Europe in 2016 – not least in Sweden and Finland. A new scientific study shows how the figures in Nature could be so wrong.
“We were very surprised. That such a big and sudden change could happen without anyone noticing was totally unexpected,” says Johannes Breidenbach, who was the lead author of the study.
“The EU’s forest policy should be based on accurate and reliable figures. I don’t think one should harvest more than is necessary, but one shouldn’t refer to figures that aren’t correct either.”
The article in Nature is based on satellite-based forest maps. Researchers from Norway, Sweden, Finland and Switzerland, combined the satel- lite-based maps with observations from the Swedish and Finnish national forest inventories. The national forest inventories are measurements of forests across the country and have been carried out for more than 100 years in Norway, Sweden and Finland.
Their results showed that the results in the Nature article could not be correct.
“The huge increase was quite simply a side effect caused by the method of identifying harvesting areas having improved since 2015,” explains Breidenbach.
The researchers compared the satellite maps with more than 120,000 forest observations, and the results showed that it was not the harvest rate that had increased, but rather the ability to detect harvests in satellite data. The measurements on the ground, in the forest, carried out by field workers of the Finnish and Swedish national forest inventories in the years before and after 2015 showed the actual harvesting, and it had not increased dramatically after 2015.
“Satellite images are a useful tool, but it’s always important to calibrate the satellite images with thorough reference data, ideally from the ground, in the forests where the trees grow,” concludes Breiden- bach.
Photo: Erling Fløistad
Purpose:
Collaboration: Contact:
An international research group with researchers from Norway, Sweden, Finland and Switzerland have combined satellite-based maps with observations from the Swedish and Finnish national forest inventories to investigate the claims of increased forest harvesting in Europe.
An international research group of researchers from Norway, Sweden, Finland and Switzerland
Research Professor Johannes Breidenbach. E-mail: Johannes.breidenbach@nibio.no, phone: +47 974 77 985.
Division of Forest and Forest Resources
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