Date of Award


Degree Name

Master of Science



First Advisor

Ruffner, Charles


Illinois has no official parameters for old-growth oak-hickory (Quercus-Carya) forests despite oak-hickory being the historically dominant ecosystem in the forested parts of Illinois (Fralish, 1997; Thompson & Dessecker, 1997). The purpose of this study was to better understand the characteristics of old-growth oak-hickory stands, as well as make management recommendations for preserving the integrity of old-growth forests and shifting second-growth stands to old-growth status. Stand structure analysis was conducted in June and July of 2022 on an old-growth oak-hickory stand (Otey-Grisley Nature Preserve) and nearby second-growth oak-hickory stand (Grisley Woods Land and Water Reserve) near Pittsburg, Illinois using dendrochronology, various stand composition analyses, and floristic assessments to compare the two forests across multiple nodes of inquiry from their canopies to their ground layers. White oak (Quercus alba L.) was of higher importance in the more open old-growth canopy than the closed second-growth canopy which had more shagbark hickory (Carya ovata L.). The old-growth stand had higher floristic quality (mean Coefficient of Conservatism and adjusted Floristic Quality Index) and lower frequency of invasive species than the second-growth stand. The dominant white oak appear to have suppressed the hickories (Carya) for over a century on both sites. However, in the sapling and seedling layer, it appears the oaks and hickories are failing to recruit into the canopy on either site. The average age of the old-growth canopy is 67 years greater than that of the second-growth canopy, the majority of which seeded in after a heavy cut in the early 1940s. The second-growth site rapidly gained early successional species after the logging. The second-growth site could come to resemble the open oak dominated character of the old-growth site. However, this will require management with fire, thinning, and invasive species treatments. The old-growth, where sassafras (Sassafras albidum L.) is crowding the understory, will also require invasive species management, prescribed fire, and thinning if it is to remain the open oak-hickory woodland it is today.




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