Energy - Environment

Stump Harvesting for Bioenergy: Climatic and Environmental Impacts

Could stumps from managed forests provide sustainable biomass in a future bio-economy or are they all needed in the forest to support other ecosystem services and biodiversity?

Currently the growth in demand for biomass is driven primarily by the conversion of the energy system away from fossil energy sources in favor of renewable sources in line with the Paris climate agreement.

An anticipated future bio-based economy will depend on large quantities of biomass also for other products such as chemicals and textiles. In forests managed to deliver pulpwood and sawtimber to the traditional forest industry only the stem wood is harvested leaving a substantial proportion of the tree biomass in the forest with roughly 20 % of the tree biomass in branches and another 20 % in stumps. This is the reason why some forest rich countries with managed forests also target stumps as a potential biomass source.

Stump harvesting means an intensification of forest management in comparison with stem-only harvesting. Before large-scale extraction of stumps from managed forests can be recommended there is therefore a need for knowledge concerning the sustainability of such a practice. This includes the climate change mitigation potential of using stumps for energy generation, impacts on long-term forest growth, impacts on soils and surrounding waters, and impacts on biodiversity.

An advanced review in WIREs Energy and Environment looks into recent research aiming to evaluate environmental impacts of stump harvest in managed forests and its sustainability.

 

Kindly contributed by Tyryggve Persson and Gustaf Egnell.

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