This research discovered four new species of beneficial fungi in northern China. These fungi belong to the genus Trichoderma, which is important for agriculture and industry. The findings expand our understanding of fungal diversity and could lead to new applications. Impacts on everyday life: • Could provide new biological control agents for protecting crops from diseases • May yield new sources of industrial enzymes and useful compounds • Helps understand fungi that affect mushroom cultivation • Contributes to biodiversity knowledge needed for ecosystem conservation • Potential applications in sustainable agriculture and green technology