Comparison of Carbon Stock and Sequestration Between Managed and Unmanaged Forests in Europe, and their Trade-off with other Ecosystem Services

Abstract

Purpose of Review Forests play a crucial role in carbon sequestration and storage, yet uncertainty remains about carbon stocks and sequestration differences between managed and unmanaged forests, which has resulted in considerable scientific and policy debate. This review synthesizes European evidence comparing managed and unmanaged forests addressing three questions: (1) what are the differences in carbon stock and sequestration for all carbon pools between managed and unmanaged forests, (2) what are trade-offs and synergies with other ecosystem services when managing for carbon, and (3) what are limitations of forest management research in identifying trade-offs and synergies between ecosystem services? Recent Findings This review shows that unmanaged forests are important for long-term carbon storage, containing 34% more above-ground biomass carbon, and 246% more deadwood, though deadwood contribution to total carbon stock is small. Soil carbon stocks only differ marginally with forest management, emphasizing the importance of avoiding losses through intense disturbance. All carbon stocks show effects of time since management abandonment. Moreover, several knowledge gaps remain: (1) carbon flux measurements for comparable managed and unmanaged forests are less common compared to stocks, but would greatly enhance understanding of carbon dynamics, (2) below-ground (root) carbon stocks are overlooked, and (3) trade-offs and synergies between ecosystem services are frequently reported, but their assessment still needs to be routinely integrated in comparative forest management research. Summary Unmanaged forests contain larger carbon stocks than managed forests, especially after long times since abandonment (>100 years). Carbon increases can be quick (deadwood), intermediate (above-ground biomass) or slow (soil). Below-ground biomass carbon and carbon fluxes in all pools remain important knowledge gaps, warranting further research.