Stand density and structural complexity modulate the effects of restorative selective cutting on aboveground carbon stocks

Forest management is increasingly recognized as a strategic adaptative measure to climate change, aiming to integrate biodiversity conservation and move beyond traditional even-aged systems globally. Selective cutting is thereby attracting attention as it is expected to maintain complex forest structure and provide multiple ecosystem services including aboveground carbon stocks. However, whether selective cutting modifies the relationships between stand structure and aboveground carbon stocks in uneven-aged, mixed species forests remains poorly understood. Using restorative selective cutting experiments conducted in southern Norway and Sweden, we investigated how selective cutting influences stand structural attributes and structural complexity, as well as the relationships between stand structure and aboveground carbon stocks in mixed stands. We found that stand density and tree size variation are the key factors determining stand structural complexity. In addition, both stand density and structural complexity drive aboveground carbon stocks. In contrast, species diversity did not significantly affect stand structural complexity, while it did negatively impact aboveground carbon stocks in selectively cut stands. We showed that selective cutting does not alter stand structural complexity nor the relationships between stand structure and aboveground carbon stocks. Therefore, selective cutting may present a promising strategy for maintaining complex stand structures beneficial for biodiversity conservation and enhancing aboveground carbon stocks. Consequently, selective cutting practices can prioritize the retention of greater tree size variation to foster both complex forest stand structure and increased aboveground carbon stocks.