Mycorrhizal fungi are central to the functioning of forest ecosystems, playing a critical role in ecological processes such as nutrient cycling and carbon storage. Mycorrhizal fungi enhance nutrient uptake by trees, forest productivity, influence decomposition, and they contribute to organic matter accumulation. This session aims to bring together research investigating the diverse roles and functions of mycorrhizal fungi in forest ecosystems, with a focus on ectomycorrhizal, arbuscular, and ericoid mycorrhizal associations. We will explore how mycorrhizal fungi drive ecosystem functioning in its broadest sense, and how these processes respond to environmental changes, from climate change to forest management. We welcome contributions from research conducted across various forest biomes and scales, ranging from the global to petri dish scale, encompassing observational, experimental, and modeling approaches. By fostering discussion and sharing cutting-edge research, this session aims to deepen our understanding of mycorrhizal fungi in forest ecosystems, clarify their ecological importance, and highlight the need for continued exploration in this rapidly evolving field.