Thinning Effects on Trade-Offs and Relative Benefits Among Forest Ecosystem Services in a Pinus koraiensis Plantation on Mt Gari, Republic of Korea

Forest thinning is a critical silvicultural practice for managing forest structure and enhancing various ecosystem services, yet its long-term impacts on trade-offs among these services remain complex. This study evaluated ecosystem services 17 years after thinning (applied in 2007) in a 40-year-old Pinus koraiensis plantation on Mt. Gari, Republic of Korea, to evaluate the effects of thinning on ecosystem services and to examine the magnitude of trade-offs between ecosystem services across different thinning treatments. Three thinning treatments were implemented in 2007: (1) control, (2) light thinning (~35% removal of stand density), and (3) heavy thinning (~65% removal of stand density). A total of 12 plots were established to assess ecosystem services 17 years after thinning. Measured variables included aboveground carbon storage (trees), understory species richness (shrubs and herbs), soil moisture, soil organic carbon, and total soil nitrogen. Relative benefits and trade-offs were quantified using standardization and root mean square error, and differences across treatments were tested using one-way. Relative benefits and trade-offs were analyzed to assess the effects of thinning on ecosystem services and how relationships among ecosystem services changed across treatments. Significantly higher aboveground carbon storage was observed in the control plot than in the other plots. The heavy-thinning plots showed the highest values for species richness and soil moisture, whereas the light-thinning plots showed the highest values for soil organic carbon and total soil nitrogen. Generally, high trade-offs were observed for pairs involving aboveground carbon storage, while pairs involving species richness showed lower trade-offs. To detect clear relationships among ecosystem services, further in-depth research and long-term monitoring are required to identify complex interactions and trade-offs.