Tree species diversity impacts on ecosystem services of temperate forests

• Temporal spectral metrics show potential for mapping of tree species diversity. • Tree species diversity positively impacts multiple ecosystem services. • Different impacts of various forest attributes on ecosystem services. Tree species diversity is crucial for forest ecosystem services as it relates to ecosystem functions. However, it remains unclear how spatially continuous tree species diversity affects multiple ecosystem services in temperate forests that undergo various management practices. We mapped the spatial pattern of tree species diversity represented by the Shannon diversity index, H’ in the temperate forests of Northeast China using 1,028 in situ observations and 846 Sentinel-2 images. We further analysed the relationships between tree species diversity and ecosystem services including carbon storage, water yield, and soil retention, while controlling for the covarying effects of multiple forest attributes including tree height, leaf area index (LAI), and stand age. Our results showed distinct spatial variations in tree species diversity across different forest management practices, with natural forests exhibiting a higher diversity compared to managed natural forests and planted forests. Tree species diversity was found to be positively associated with improved ecosystem services, particularly water yield and soil retention, while the effects plateaued above diversity of 1.0 (Shannon index values). We also showed that LAI was the most important factor influencing carbon storage, while tree species diversity and stand age were crucial for water yield and soil retention. These results highlight the importance of maintaining diverse tree species to improve ecosystem services in temperate forests, providing a robust framework for effectively monitoring and managing forest ecosystems with regards to sustainable forest functioning.