Historical forests of the eastern US were open old growth forest ecosystems, not closed forests and not successional. Fundamental ecology and silviculture of temperate open forest ecosystems remains ill-defined because these forests do not match traditional silvicultural or ecological concepts. Open forests are characterized by simple internal stand structure consisting of overstory trees of fire-tolerant oak and/or pine species. Limited tree densities below the overstory trees allow co-existence of grasslands in the groundlayer. Frequent surface fire provides a mechanism to maintain open oak and pine forests with a grassland ground layer through removal of tree regeneration, which otherwise would capture the growing space from herbaceous plants and fill in the midstory. We have proposed that declining early successional bird species are instead open forest bird species that relied on the relatively permanent grasslands ground layer in historical open forests. Open forest ecosystems bridge the canopy spectrum between treeless grasslands and closed forests. Delivering this research has the potential to be transformative to pedagogy and management, in ecology, silviculture, and wildlife ecology, by providing an alternative ecosystem and management option that is not a clearcut or closed forest.