An assessment of the competitive ability of oak species in the central hardwood region using both pre-harvest treatment data and stem analysis techniques
The density of advance regeneration of oak species has been in decline across the Central Hardwood Region (CHR) for the past 50 years. This phenomenon has been accredited to many different factors, ranging from predation and browse by wildlife, to human induced changes in the environment which include massive clearcutting, land use change from forest to agriculture, and suppression of fires which played an intricate role in the development of oak systems across the CHR. The objectives of this research project were to compare densities of oak advance regeneration across two different environmental gradients within the CHR, in particular the mesic uplands of south central Indiana in the Hoosier National Forest and the xeric uplands of the Missouri Ozarks located within the Sinkin Experimental Forest. In addition, we compared the development of white oak species versus their competitors following a disturbance (clearcutting) up until the stem exclusion stage of forest development. We used a mixture of ordination and regression techniques to evaluate our objectives. Our findings suggest that the distribution of red oak species advance regeneration is correlated with xeric sites that exhibit convex topography in Missouri. Environmental variables in Indiana were limited in their range and likely were the reason we did not detect any environmental trends in advance regeneration within Indiana. When considering environmental influences on white oak development following a clearcut in Indiana we did not detect any significance in terms of the likelihood of a white oak achieving a higher canopy position over its two nearest competitors. Studies of this nature are important for the continued development and prorogation of oak forests across the CHR.^
Michael Jenkins, Purdue University.