Can forests save us from climate change?

If you think that sustainable forest management can be a major contributor to mitigating climate change, then you had better not hold your breath. At least not according to the findings in a recent study published in Nature by an international team of scientists led by Vrije University Amsterdam. The team included postdoc Sylvestre Njakou Djomo from the Department of Agroecology at Aarhus University in Denmark.

The scientists found that the additional climate benefits through sustainable forest management will be modest and local rather than global. Even if Europe's forests are managed in such a way that their carbon sequestration is maximised it will not impact the climate significantly.

Instead, it seems that the forests themselves will need to be adapted to climate change.

- We suggest that the primary role of forest management in Europe in the coming decades is not in protecting the climate but in adapting the forest cover to the climate of the future in order to sustain the provision of wood, as well as ecological, social and cultural services, while avoiding climate feedbacks from fire, wind, pests and drought, say the authors of the article.

Three forest management scenarios tested

The team of scientists improved a complex computer model to calculate the amount of carbon, energy and water that is trapped or released by managing a forest. They then analysed the effects of three different forest management strategies. The three scenarios reflect different ideas of how forest management in Europe might contribute to mitigating climate change and are as follows:

• maximise the carbon sequestration ability of the forest sector
• maximise the reflectivity of the forests
• reduce the surface temperature near the forest.

Sustainable forest management has the potential to slow global warming by removing CO₂ from the atmosphere. Forest management that has a focus on minimising CO₂ can thus remove seven gigatons of carbon from the atmosphere by the year 2100.

- This should result in a cooling of the upper atmosphere. However, we did not see the expected impact because other processes play a part and affect, for example, wind speed and air humidity, Sylvestre Njakou explains.

Alternatively, forest managers could practice climate-based management by converting evergreen forests to deciduous forests. This would result in a cooling of about 0.3º C in the spring in Scandinavia and the Alps. However, the effect is too small to have a global impact.

- On the other hand, it would decrease the wood available for harvest by 25 percent, Sylvestre Njakou points out.