Effects of Timber Harvesting on the Understory Oak Regeneration in Upland Oak Forests in the Missouri Ozarks

Abstract

In the Missouri Ozarks, widespread oak decline in the overstory, along with failure to attain adequate regeneration have plagued oak-hickory forests. The reason for this has largely been attributed to long-term fire suppression and low-intensity timber management that has little impact on the main canopy. The Missouri Ozark Forest Ecosystem Project (MOFEP) was initiated in 1989 by Missouri Department of Conservation as a long-term, landscape-level study designed to evaluate the effects of timber harvest activities, both even-aged and uneven-aged, on oak forest ecosystem attributes. We used sixteen-year (1990-2006) MOFEP data to evaluate oak regeneration under various stand treatments. Pre-harvest data (1990-1995) indicated that oak regeneration in both the white oak and red oak groups had an inverse relationship with overstory density. Changes in understory density of the two groups were examined following treatments that included clearcutting, intermediate harvest (e.g., thinning), single-tree selection, group selection, and a no harvest control. The post-harvest data (1997-2006) indicated that in 2001, seedling (\u3c1.5 inches dbh) density of white oak and red oak group species were 17 times and 13 times greater respectively than in 1995 on the clearcut sites. All of the other treatments had slight, but non-significant increases in oak seedling density. In 2006, sapling (1.5 inc