I wouldn't say that. There's plenty of behaviors where plants and fungi act in the interest of the community as a whole. Mature forests are made of late-successional species. These species could only possibly grow after earlier succession species had "prepped the soil" (nurtured the soil ecology, transitioned the nitrogen cycle from ammonia to nitrates, etc) and provided shade to allow them to grow. Since these trees are dependent on the well being of so many other species there is plenty of incentive for them to act in ways that we might call "selfless"