Bob Edgin

Fire History of a Post Oak (Quercus stellata Wang.) Woodland in Hamilton County, Illinois

Abstract Cross-sections of 36 post oaks (Quercus stellata Wang.) were examined to determine the fire history of a post oak woodland in Hamilton County, Illinois. The 226-year tree ring record contained three distinct periods; a fire era from 1776 to1850 having a mean fire return interval of 1.97 years, a fire-free period from 1851 to1884, and a second fire era from 1885 to 1996 having a mean fire return interval of 1.44 years. The fire-free interval corresponds with the rapid settlement of Hamilton County during 1850–85. The fires between 1770 and 1850 are considered landscape fires associated with Native Americans and/or early European settlers, while those between 1885 and 1996 are thought to be due to burning of local woodlands, a practice that became increasingly less common in the late 20th century. Three post oak cohorts were identified, including 211–224 year-old (217-year mean), 137–151 year-old (144-year mean), and 104–115 year-old (105-year mean) age classes. Post oak recruitment ended and fire sensitive hickories (Carya ovata and C. tomentosa), black cherry (Prunus serotina), sassafras (Sassafras albidum), and black oak (Quercus velutina) now dominate the seedling and sapling layers of the woodland.

Vascular Flora of Gray's Post Oak Woodland, Saline County, Illinois

Abstract Grays Post Oak Woodland is an open wooded community located on the western edge of the Wabash Border Natural Division about 9 km southeast of Harrisburg, Saline County, IL. Associated with a clayey soil missing most of the surface layer, the trees were stunted and gnarled. Quercus stellata dominated the canopy, accounting for nearly all of the importance value. Although six other tree species were present, few individuads exceeded 15 cm dbh. The open understory contained few saplings, averaged 1520 stems/ha, with young post oaks common. The herbaceous layer was sparse with a bare ground and litter cover of 48.90%. Danthonia spicata dominated, along with various moss and lichen species, some tree seedlings, and Carex spp.

Revisiting dogwood anthracnose in Illinois

Abstract Dogwood anthracnose (Discula destructiva) was first discovered in Illinois in 1995 at Dean Hills Nature Preserve, Fayette County. In the original study, individuals of flowering dogwood (Cornus florida) showed a 97% increase in infection by dogwood anthracnose between July 1995 and August 1996. As all size classes of flowering dogwood were infected, it was predicted that the disease would probably cause the extirpation of this species at the site. Though not extirpated, flowering dogwood has not recovered from the initial infection (1995), when 3475 healthy stems/ha were encountered. Since that initial study, total flowering dogwood stems recorded for the site ranged from a low of 110 stems/ha in 1996, to 540 stems/ha in 2002, and 345 stems/ha in 2004.

Status and Distribution of Illinois Populations of Stenanthium gramineum (Ker-Gawl.) Morong, Grass-Leaved Lily (Liliaceae): an Endangered Plant in Illinois

Abstract Stenanthium gramineum (Ker-Gawl.) Morong (grass-leaved lily) is known historically from 19 populations in 13 counties in Illinois. Seven populations in the southern one-third of the state are extant and three extirpated; nine could not be located. Population size ranged from 106 plants at the Richand County site to 611 at a Pope County site. All of the populations occupied an area of 75 m2 or less. Flower production was not observed at any of the sites in 2002. The populations occurred on acid soils in a floodplain forest, in upland forests with north- and east-facing slopes, and a gravel wash of an intermittent stream.

Vegetation composition and structure of Eversgerd Post Oak Flatwoods, Clinton county, Illinois

Abstract Eversgerd Post Oak Flatwoods is a 16 ha woodlot that is part of an extensive band of timber associated with the broad Kaskaskia River valley in the Southern Till Plain Natural Division of Illinois. This flatwoods was studied to determine its woody composition and structure, and the effects of fire suppression on canopy closure and plant succession. Tree density within the site averaged 266 trees/ha with a basal area of 24.8 m2/ha. Quercus stellata Wang. (post oak) dominated the overstory and woody understory with an importance value of 171 (200 possible). Quercus bicolor Willd. (swamp white oak) and Q. palustris Muenchh. (pin oak) were common species in a shallow depression, accounting for their second and third in importance value ranking. The forest has an open, park-like appearance. Small woody saplings averaged 820 stems/ha and large saplings averaged 221 stems/ha. Grasses and sedges dominated the herbaceous layer; Danthonia spicata (L.) Roem. & Schultes and Carex cephalophora Willd. were the dominant species. The large number of post oaks with low branches and branch scars indicate that this forest was more open in the past.