In nature such a mix of species is inherent, a guard against runaway infestations. Durbin, K. Oregon. The Mountaineers, p. 55. The Role of Fungus in the Forest Fungi fill many roles. They act as decomposers, cause disease, and live inside foliage, producing chemicals distasteful to insects.
Thousands combine with algae to form lichens.
McNulty, T. Washington. The Mountaineers, p. 99. These elaborate underground networks even transfer carbon and nutrients from tree to tree, enabling shade-bound trees to benefit from the photosynthesis if neighbors that have succeeded in reaching the canopy above. Some 60 percent of the carbon produced by photosynthesis actually goes to roots and mycorrhizae within the soil. This symbiosis begs the question of individual organisms living independently and points instead to the unity of the forest ecosystem.