Timber Harvesting, Prescribed Fire and Vegetation Dynamics in the Missouri Ozarks

—Little is known about the response of Missouri Ozark ground flora to silvicultural treatment. In this project, we examined herbaceous and woody species response to various thinning regimes and prescribed burns over several years at the Missouri Ozark Forest Ecosystem Project (MOFEP) and the Chilton Creek Management Area (CCMA). On MOFEP, ground flora and woody species regeneration data were collected across nine sites and three harvest treatments: 1) uneven-aged management, 2) even-aged management, and 3) no-harvest management. On CCMA, ground flora and woody species regeneration data were collected across burn units with different fire frequencies: 1) burned in 1998 and 2002, and 2) burned annually since 1998. Ecological Landtype Phase (ELTp) was used to stratify plots and for comparison and contrast among treatments. For woody regeneration up to 1 m, seedling and sapling development was greater on units that have been burned twice than units burned annually. For both fire frequencies and across ELTps, white oak (Quercus alba) dominated regenerating species. White oak regeneration was also abundant in most of the areas on MOFEP, particularly the uneven-aged plots. Successional trajectories were developed to examine treatment and ELTp effect on species change over time. The trajectories appear to be influenced by treatment as well as ELTp. Burning homogenized the ground flora vegetation on the sites, and decreases variability among ELTps, creating a consistent trajectory across ELTp. The effects of thinning and clearcutting, however, seem to be related to ELTp, therefore these ecological units can be used to understand and possibly predict the influence of specific management on vegetation. Long-term studies of sufficient spatial extent are critical for understanding response of the vegetation communities associated with areas under active forest management. Furthermore, management for forested lands continues to develop as data reveal the consequences of various silvicultural approaches. Several large-scale studies have been conducted in attempts to characterize effects of forest management. For example studies in the Pacific Northwest (e.g., Halpern and Spies 1985, Franklin and others 2002), the Appalachians (Gilliam and others 1995, Meier and others 1995), and the Lake States (Metzger and Schultz 1984) underscore the need to include long time periods, realistic management objectives and large physical scale when examining effects of forest management activity. Ecological land classification, a hierarchically structured, multi-factor approach for mapping ecological units at multiple scales, has been shown to be helpful in quantifying variation in ecological processes (Host and others 1987). As such, it may be valuable as a framework to examine the long term influences of management. This classification system characterizes the landscape by ecological variables including vegetation structure and composition. Management units 10’s to 100’s of acres (approximately 5-50 ha) in size can be defined by soil, aspect, geology and vegetation (Ecological Land Type phases [ELTps]), and represent a typical management level unit. Although few studies have incorporated the use of Ecological Classification Systems or specifically ELTp as an approach to understanding the effects of management, evaluation of the ecological units and their ability to describe variation in ground flora structure and composition, and response to management will contribute to the overall utility of an Ecological Classification System (ECS). Numerous research efforts have examined the effect of silvicultural practices on important timber species, woody regeneration, and to a more limited extent, ground flora species. Changes in herbaceous species composition can provide a sensitive measure of ecologically relevant changes in the environment †Plant Ecologist (ANS), National Park Service, Wilson’s Creek National Battlefield, Republic, MO 65738; and Associate Professor (RMM), Department of Forestry, 203 Natural Resources Building, University of Missouri, Columbia, MO 65211. RMM is the corresponding author: to contact, call (573) 882-8835 or e-mail at muzika@missouri.edu