Oak regeneration before and after initial restoration efforts in a tall grass oak savanna: conference paper

Unsuccessful oak (Quercus spp.) regeneration could result in losses of the rarer portions of the midwestern North American oak savanna region, including the tall grass oak savannas. We undertook this study to understand the effects of restoration on promoting growth of naturally occurring Q. alba seedlings in a degraded tall grass oak savanna in Iowa, USA. Initial restoration efforts, which involved mechanical removal of encroaching overstory trees, promoted positive increases in height and basal diameter of Q. alba seedlings in canopy gaps. Conversely, seedlings growing under Q. alba tree canopies in restoration areas and seedlings in control areas failed to display height and diameter increases. As seedlings were most abundant beneath Q. alba canopy trees, this created a dichotomy whereby seedling source (beneath canopies) and proper conditions for growth (in canopy gaps) were not one in the same. Although this restoration is still in its early stages, these results suggest that Q. alba regeneration may be successfully promoted at this site.