Manipulating forest structure and ground flora composition for the restoration of oak woodlands and the reconstruction of oak savannas in Central Missouri

Abstract

Managers across the central US are interested in restoring once abundant ecosystems such as savannas and woodlands. These restorations are inundated with challenges like creating the appropriate native plant structure and composition. This project will evaluate methods to 1) reintroduce woody structure to a restored prairie to create a savanna, and 2) establish native woodland ground flora in a recently thinned mature oak stand for woodland restoration. Savannas require frequent fire for maintenance; as such, newly planted trees in a prairie will require protection from frequent fire. For our first project objective, we planted 900 oak (Quercus) seedlings of five species grown by two nursery production methods [containerized root production method (RPM) or bare-root] and used weed barriers and a mechanical fuel removal treatment to protect them. Species and stock type selection were the most important treatments in establishing oak trees in a restored prairie, while the mechanical fuel removal and weed barrier treatments had little effect. Returning a degraded oak forest to a woodland community may require active seeding of woodland ground flora and seedbed manipulation due to a depauperate seed bank and low potential for desired species to colonize the site. For our second project objective, establishing ground flora in structurally restored woodlands, we seeded a diverse mix of native herbaceous species that have various light tolerances on plots of varying overstory tree density where the litter was either raked or not. Reduced basal area, seeding of native ground flora, and time since treatment were significant for increasing abundance, diversity, and the quality of the plant community, while raking had little effect.