The Composition of a Post Oak Forest in South-Central Oklahoma

Wm. T. Penfound
1963 The Southwestern naturalist  
The black willow forest under discussion is located on the north shore of Lake Texoma, approximately one mile west of the University of Oklahoma Biological Station. near W1llis, Oklahoma. It had its origin on river sand of quaternary age when the lake was impounded in 1945. The stand (about seven acres) slopes gently to the south with the soil of the lakeward fringe usually covered with one to six inches of water. The forest consists of a nearly pure stand of black willow (8alix nigra)' with an
more » ... lix nigra)' with an average measured height of fifty-five feet and an age of fifteen years. The understory comprises a shrub stratum of OephaZanthus occidentall8, a tall herb layer of Eupatorium serotinum, and a low stratum of Diodia virgintana, Hydrocotyle 'Verticillata, and Rubus trivtaZiS. Trees were sampled by means of the arms-length rectangle method (Penfound and Rice, 1957). The method was modified by using a predetermined length of rope so that the rectangles being studied would be of constant size (0.01 acre). Woody shrubs and vines were sampled by means of quadrats of four square meters, and herbs were studied by the aid of 0.1 square meter quadrats. The forest comprised five species of trees, two shrubs, five woody vines, three herbaceous vines, and thirty-siX herbs. The upper canopy consisted entirely of black willow with 357 trees per acre and a relatively high basal area of 113 square feet per acre. No willow seedlings or saplings were encountered. Occasional seedlings of Diospyros 'Virginiana were observed. It is improbable, however, that sufficient seedlings and saplings of this species will be available to revegetate the area when the willow trees have disappeared. Under the circumstances, one cannot help but wonder what the future of the area wlll be. The fragmentary shrub stratum consisted primarily of Oephalanthua ocmdentalis, which possessed a very low areal cover. The herbaceous cover, however, was comparatively heavy and almost continuous (Table I) . This was due, presumably, to the relatively high light intensity that prevailed (695 footcandles) in the forest. A notable zonation of herbs occurred in this stand of black willow. Hydrocotyle 'Verttcillata was the dominant species in the very wet and often inundated soil near the lake shore. Near the middle portion of the stand Diodia ";,rginiana was the predominant species but was replaced by Eupatorium serotinum on the driest portion of the stand. SUMMARY
doi:10.2307/3669556 fatcat:zhgpdobqjnesvo66kunf5q6olu