Date of Award

Spring 5-1-1976

Document Type

Thesis

Degree Name

Master of Arts (MA)

Department

Life Sciences

First Advisor

Marion T. Jackson

Second Advisor

Paul Mausel

Third Advisor

John O. Whitaker Jr.

Abstract

This research used the data on witness trees found in the surveyors' records of the General Land Office surveys of 1805-1815 as the basis for studying the primeval forests of unglaciated southern Illinois. Via computer, the random pairs and closest individual methods of plotless sampling were used to develop stand attributes tables, with soil association boundaries defining the limits of forest stands. A vegetation map was developed from these stands. Four major forest types were delineated: Upland Oak, nixed Hardwoods, Swamp Forest, and Floodplain Forest. The Upland Oak Forest, with lowest density (175.9/ha or 71.2/acre) and basal area (21.3 rn 2/ha or 92.9 ft 2/acre) was located in the Shawnee Hills uplands. It consisted primarily of vlhite and black oaks and hickories on drier soils of thin loess. The more mesic ~!ixed Hardwoods Forest, where density (281.4/ha or 114.0/acre) and basal area (38.3 m2/ha or 167.0 ft 2/acre) were highest, was found mainly on the thicker loess of the western Thebes Hills. It was dominated by American beech, white oak, sweetgum, and tuliptree. The annually-flooded inland lowlands supported a Swamp Forest of elms, ashes, oaks, sweetgum, and hickories. The Floodplain Forest, of sycamore, hackberry, cottonwood, elms, and ashes, occurred on the alluvial soils of the Mississippi River floodplain. Prairie was found only at two scattered locations on the upper Mississippi floodplain, and cypress swamps were concentrated in the Saline River and former Ohio River Valleys. Description of the study area as Western Mesophytic, consisting of a mixture of climax and successional communities, concurs with E. Lucy Braun in her work on the eastern deciduous forest. Previous maps showed less detail, failing to indicate the mixed nature of the area. The study of E. Lucy Braun came closest to agreeing with the new map. Size class analysis of witness trees indicated that surveyors were biased in usine even inches and whole feet when measuring diameters. The possibility that American beech may have migrated from the south or southwest was demonstrated by its concentration in the Thebes Hills.

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