A Long-term Study of Seedling Regeneration for an Oak Forest Restoration in Cleveland Metroparks Brecksville Reservation, Ohio

Abstract

The Cleveland Metroparks Brecksville Reservation initiated an oak forest restoration in 1990, using thinning and burning to encourage regeneration of oak forest species. In 96 quadrats (81 treatment and 15 control), understory woody species were inventoried from 1992 to 2002, and canopy opening was quantified. Six years into the study, the entire reservation became heavily populated with white-tailed deer (Odocoileus virginianus) and gypsy moths (Lymantria dispar), complicating the restoration efforts. During data analysis, understory woody species were classified into oak forest type and nonoak forest type, and three distinct phases became evident (phase 1: 1992–1994 treatment effects only, phase 2: 1995–1999 period of invasion by deer and gypsy moths, and phase 3: 2000–2002 post-invasion period). Both oak forest and nonoak forest species increased in the treatment area over the control area. During phase 1, burning encouraged oak seedlings, and thinning reduced competition from nonoak species, suggesting a temporarily successful restoration attempt. The intense gypsy moth browse in phase 2 reduced the number of oak seedlings, creating conditions favorable to nonoak species. The quantity and diversity of seedlings increased as gypsy moths opened the canopy. Deer browsed most species, oak and nonoak, even when deer populations decreased and more species were available. Original treatment effects may have been continuing in phase 3; however, additional years of study are needed.