Researchers claim Europe’s trees causing global warming

Planting trees is perhaps the best and most widely-known mitigative measure when it comes to climate change. However, a new study published Friday in the journal Science posits that planting the wrong kind of trees may, in practice, stoke global warming.

Using historical data about trees planted in Europe since 1750, a team of French researchers created a computer modeling that showed what kind of impact these forests have had on climate change.

Afforestation and forest management are recognized as key strategies for climate change mitigation in the Paris agreement within the United Nations Framework Convention on Climate Change (UNFCCC). Afforestation and forest management are generally expected to have the potential to slow global warming by removing CO2 from the atmosphere. However, the new study shows that, despite a considerable increase in forest area and the onset of widespread production-oriented management since 1750, European forests failed to realize a net CO2 removal from the atmosphere. By extracting wood from unmanaged forest and bringing these forests under production, humans released carbon to the atmosphere, otherwise stored in the biomass, litter, dead wood and soil of the forest. Kim Naudts, lead author of the study explains: “Even well managed present-day forest store much less carbon than their natural counterparts in 1750”.

Besides wood harvest, the onset of production-oriented forestry also massively converted deciduous forest to coniferous forest by favouring commercially successful species. This resulted in changes in water and energy exchange with the atmosphere, which contributed to climate warming rather than mitigating it. Kim Naudts concludes: “Our results show that not all forest management contributed to climate change mitigation. The key question is now: can we design a forest management strategy that cools the climate and at the same time sustains wood production and other ecosystem services?”

Agencies/Canadajournal