PARENT SESSION
Poster Session # 14: Forest Ecology.

Wednesday, August 6 Presentation from 5:00 PM to 6:30 PM. SITCC Exhibit Hall B.

Historical change and future predictions of vegetation structure in a central Illinois woodland.

Smith, Japhia^*,1, Anderson, Roger¹, ¹ Illinois State University, Normal, IL

ABSTRACT- Historically, many Illinois upland woodlands were dominated by shade-intolerant oak and hickory species that required periodic fires for their maintenance. Fire cessation associated with European settlement permitted aggressive invasion of these forests by fire sensitive but shade-tolerant sugar maples, which have displaced other native tree species. This vegetation change is displayed by our study site, the 13 ha Thaddeus Stubblefield Illinois Nature Preserve in Funks Grove, IL. Changes on the site are documented by historic tree data from Government Land Office (GLO) Survey Records, and tree and sapling data collected in 1977, 1984, 1994, and 2001. Based on GLO records, the leading trees in the original grove were white and red oak, ash, and elm. In 1977, the leading tree species was American elm, which was replaced by sugar maple as the leading species in the 1984 sample and in all subsequent samples. Tree diversity as measured by the Shannon-Wiener Index has progressively declined from historic times. A comparison between the diversity of the tree stratum and the sapling stratum over time indicates increasing similarity between strata while diversity decreases overall. We also examined the impact of loss of the elms on the diversity of the forest. STANDSIM, a stochastic forest model, was used to make predictions about future vegetation change based on current and historical data.

Key words: STANDSIM, Forest vegetation