Stump Sprout Dominance Probabilities of Five Oak Species in Southern Indiana 20 Years after Clearcut Harvesting

—Oak (Quercus spp.) stump sprouts are vital to sustaining oak’s presence and long-term dominance when regenerating oak or mixed-hardwood forests in southern Indiana. A study was initiated on the Hoosier National Forest in southern Indiana in 1987 to predict the sprouting potential and dominance probability of oaks. Before clearcut harvesting, we sampled 2,188 trees of fi ve oak species and measured tree age and diameter at breast height along with site index to develop sprouting and dominance probability models for subsequent follow-ups at years 1, 5, 10, 15, and 20. For the current study a dominant oak was one that had one or more competitively successful sprouts per stump 20 years after clearcutting. Two species were in the white oak group—white oak (Q. alba L.) and chestnut oak (Q. prinus L.)—and three in the red oak group—black oak (Q. velutina Lam.), scarlet oak (Q. coccinea Muenchh.), and northern red oak (Q. rubra L.). We used logistic regression to develop preharvest predictive models for sprouting potential and dominance probabilities as well as postharvest models for dominance probabilities of the fi ve species. Th e 20-year results will be compared to results obtained 1, 5, 10, and 15 years after harvest (Weigel and Peng 2002, Weigel and others 2006). Managers can use our models to anticipate regeneration failures before harvesting or sprout success after harvest. 1Forester (DRW), Hoosier National Forest, 811 Constitution Ave., Bedford, IN 47421; Research Forester (DCD), Northern Research Station, University of Missouri-Columbia, Columbia, MO 65211; and Professor (CJP), Indiana University, 201 North Rose Ave., Bloomington, IN 47405. DRW is corresponding author: to contact, call (812) 276-4774 or email at [email protected]. INTRODUCTION Oaks are important for timber, wildlife food, and stand biodiversity. Oak regeneration continues to be a problem (Lorimer 1983, 1989). Oak advanced reproduction has been considered the main source of stems for the future forest (Sander and others 1976, 1984). One component of the future stand that is often overlooked is oak stump sprouts. Th e contribution of stump sprouts is overlooked in part because of the limited information about the percent of oak stumps that sprout and produce competitively successful sprouts. Th us, predicting the success or dominance of stump sprouts following overstory removal is important for understanding the role of stump sprouts in regenerating oaks. Early research showed that parent tree age, diameter, and site quality were signifi cant predictors of stump sprouting (Roth and Hepting 1943, McGee 1978). In Missouri, parent tree age, stump diameter, and site index were important predictors of oak stump sprouting (Johnson 1977, Dey and others 1996). In northern lower Michigan, parent tree age and stump diameter were important predictors of stump sprouting for white oak (Quercus alba L.) and black oak (Q. velutina Lam.) (Bruggink 1988). Diameter at breast height (d.b.h.) was a signifi cant predictor for white, black, northern red (Q. rubra L.), and chestnut oak (Q. prinus L.) in