Ecosystem services provide regulation, provisioning, support, and cultural benefits for human survival, but it needs to be clarified how the trade-off/synergy relationships can be used to optimize function. Based on the Web of Science (WOS) and China National Knowledge Infrastructure (CNKI) databases, we collected 254 articles on the ecosystem trade-offs/synergies and functional optimization. Through a systematic review of the literature, this paper summarized the research progress and landmark achievements from three aspects: trade-offs/synergies, functional optimization, and evaluation methods. The results indicated the following: (1) In terms of the number of articles published, there were no reports before 2005; from 2006 to 2022, the annual number of published papers increased from 1 to 72, showing an overall growth trend year by year. This mainly includes three stages: initial (1970–2005), slow development (2005–2014), and rapid development (2014–2022). (2) In terms of research areas, focus was placed mainly on Asia, North America, and Europe, accounting for 40.47%, 25.55%, and 15.07% of all regions, respectively. (3) In the future, it is necessary to focus on scientific issues such as the improvement of forest ecosystem functions, the trade-off/synergy relationships between services, the scale of spatiotemporal research, and the driving factors and evaluation methods for the management of rocky karst desertification. The aim is to provide a theoretical basis to optimize the forest ecosystem service functions.

Understanding the multi-scale and multi-factor driving mechanisms of ecosystem services (ES) change is crucial for combating the severe degradation of the ecosystem. We reviewed 408 publications on ecosystem structure, biodiversity, and plant functional traits related to ES in forest ecosystems. Strategies were proposed and key scientific issues were pointed out to improve the forest ecosystem in the karst desertification area. The results showed that the total number of publications has increased rapidly since 2014, of which biodiversity studies contributed the majority. China, the USA, and Germany were the top three countries, accounting for 41%, 9%, and 6% of the research, respectively. Further review found that structure, species diversity, and functional traits have an apparent effect on ES at different (macro, meso, and micro) scales. The optimization of tree structure contributes to the improvement in ES provision and the regulation capacity. Species diversity plays an important role in provision services, while functional diversity is equally important in regulation services. Plant root functional traits can not only help regulation services but also determine the species and structure of rhizosphere microbial communities. The response of ES to a certain factor has been extensively reviewed, but the interaction of multiple driving factors needs to be further studied, especially in how to drive the supply capacity of ES in multi-factor and multi-scale ways. Clarifying the driving mechanism of ES at different scales will help to improve the supply capacity of the ecosystem and achieve the goal of sustainable development.

Karst desertification control forests are essential for ecosystem multi functionality, but the trade-offs/synergies are unclear for forest ecosystem services. In order to clarify the trade-offs/synergies, this study was conducted on eight forest communities in a karst desertification control area and was based on vegetation surveys and structural and functional monitoring. It analyzes water holding capacity, species diversity, soil conservation, and carbon storage characteristics and their trade-off/synergies. The results indicate the following: (1) The Cladrastis platycarpa + Cotinus coggygria community (H1) had the highest water holding capacity and species diversity with values of 252.21 t·hm⁻² and 2.56, respectively. Soil conservation was highest in the Zanthoxylum bungeanum + Glycine max community (H6), with an index value of 1.56. Carbon storage was the greatest in the Tectona grandis community (H8), at 103.93 t·hm⁻². The results of these studies have shown that there are significant differences in different types of forest community ecosystem services. (2) Water holding capacity, species diversity, soil conservation, and carbon storage, all have synergistic relationships, suggesting a trend towards synergistic enhancement between the services. (3) The species diversity of the forest ecosystems was shown to be in a trade-off with carbon storage and soil conservation, which suggests that the services are in competition with each other. To further improve the service capacity of forest ecosystems, the trade-offs between the regulation of forest community structure and function and the improvement of services should be optimized.