Abstract: Understory economic management is an important approach to increase the income of local residents, 〖but its effects on ecosystem services and their trade-offs remain unclear. Qingyuan Manchu Autonomous County of Liaoning Province (hereinafter referred to as Qingyuan County) is a typical forest area in the eastern part of Northeast China. Using the methods of field survey, questionnaire, "3S" technology, InVEST model and scenario analysis, we examined the development of understory economy and its effects on provisioning and regulating services in Qingyuan County from 2015 to 2024. The optimal management and its spatial pattern were proposed. The results showed that the managed area of the understory planting increased from 23400 hm² in 2015 to 47400 hm² in 2024, with a 102.29% increase. As the increase in managed area, soil conservation decreased by 1.36% and water yield increased by 8.72%. Timber production decreased by 0.49%, and understory economic provision increased by 108.18%, with an increase of 0.67% in total provision value. The scenario analysis showed that the provisioning service per unit area of forest first increased and then decreased, and soil erosion and water yield showed an increasing trend with the expansion of the managed area of plantation forest and natural forest. Provisioning and regulating services showed a strong trade-off relationship, and a significant turning point was identified. In order to reduce the tradeoffs between provisioning and regulating services and to balance understory economy management and ecological conservation, it is recommended that the proportion of managed area of understory economy in plantation forests and natural forests should not be higher than 50% and 20%, respectively. Our results provide a theoretical basis for the rational development of the understory economy, and have important significance for realizing the sustainable development of forest region and the goals of rural revitalization in Northeast China.

Key words: understory economy, InVEST model, ecosystem services, trade-off, forest management