Tree species composition and oak competitive status in upland hardwood stands approaching mid-rotation in southern Illinois

Quercus (oak) species are important primary producers of the Central Hardwoods Region. They are one of the most valuable timber species in the region and support a wide variety of wildlife species. Clear-cutting has been the preferred silvicultural technique throughout the 1900's when trying to regenerate the oak species. Recently, oak regeneration failures have been well documented across the Central Hardwood Region. Main factors include the absence of fire and increased stocking levels of non-oak species in forest understories. In 2006, inventories were conducted in 74 upland hardwood stands that were clear cut on the Shawnee National Forest between 1980 and 1990. Stated objectives for the clear-cuts were to regenerate the stand to desirable upland hardwoods such as white and red oak, Liriodendron tulipifera, and Fraxinus americana. The study was conducted to determine the effects of landscape position and physiographic region had on tree distribution and oak crop tree competitive status.;Oaks decreased from 55% pre-harvest volume to 16% post-harvest density across all study sites. Oaks were limited to exposed, dry landscape positions. Oak competitive status was similar across all landscape positions. Mesophytic competitors were widely distributed across the landscape, including Prunus serotina, Acer saccharum and Liriodendron tulipifera. Liriodendron tulipifera has emerged as the most serious competitor to oak species. Liriodendron tulipifera represented 14% of the total density, and 29% of the total basal area across all study sites.;Intermediate treatments can be used to improve the competitive status and development of oak species where regeneration rates are insufficient. Crop tree release and thinning by basal area control have been proven to increase diameter and height growth and improve the development of live crown ratio of oak species. Treatments need to be implemented as early as possible in mid-rotation stands in order to take full advantage of the benefits.