Evaluating the impact of tree thinning and prescribed fire management on forest structure and tree growth in an oak savanna under restoration

David Goldblum
Associate Professor
Department of Geography
dgoldblum@niu.edu

Project Description: REU students will work with NIU researchers currently studying the vegetation dynamics of anactive and large-scale oak savanna restoration in Illinois. The Nachusa Grasslands is 2,800 acres of prairie remnants and oak savannas currently undergoing active restoration management.  Starting in 1986 with the purchase of 250 acres, Nachusa Grasslands has been recreating a vision of what would have been the local native ecosystems 200 years ago.  Hundreds of dedicated volunteers have collected seeds to replant former corn and soy bean fields, removed weedy species, and reintroduced fire to the local ecosystems. Through both fieldwork and laboratory analysis, REU students will study the impact that an ongoing oak savanna restoration is having on one of the last remaining oak savannas in Illinois. Students will work with Nachusa Director Bill Kleiman and the NIU mentors to examine how we measure and evaluate success in such a restoration project. Students will employ ecological and biogeographical field and laboratory methods to quantify vegetation changes occurring since the start of the restoration of an oak savanna. More specifically, this research aims to determine the extent to which contemporary degraded oak savanna communities are different from pre-settlement oak savannas and how ecosystem management can direct oak savanna ecosystems towards more natural conditions.  We will collect important vegetation data (tree species density, tree ages, tree growth rates using tree rings, and photosynthesis rates) to understand the ecosystem’s structure, function, and composition.  This information can be used to establish sustainable restoration goals, as well as provide a baseline by which to measure the success of ongoing and future ecological restoration projects.