The high elevations in the Southern Appalachians house unique, non-forested grass- and shrub-dominated communities. These communities are of conservation concern because they provide habitat for many rare and endemic plant and insect species and they have high recreation value because they provide scenic overlooks along many of the hiking and horse trails in the region. Many of these forest openings are identified as likely to be converted to forest because trees have begun to establish within these former forest openings. Various federal, state, and private landowners have attempted to actively manage these forest openings with prescribed fire, imported herbivores, and manual cutting of trees; however, in many instances scientists lack sufficient information about how and when these openings are converting to forest. Dendrochronology offers a valuable tool for reconstructing the spatial and temporal patterns of tree invasion. In this study, three existing forest openings and one former opening were studied to identify (a) when trees established, (b) what was the pattern of establishment (e.g., edge to interior), and (c) determine whether the species composition of the newly established forest differs from that of the surrounding forest.
Results/Conclusions
The interior of the forest openings are hotter and drier than the surrounding forest which seems to retard successful establishment of trees within the openings. However, the areas of the opening immediately adjacent to the forest edges provided a more suitable habitat for tree establishment and therefore tree establishment in forested openings proceeds from the edge to the center of the openings. This is reflected in the ages of the trees which are younger along the edge of the openings and older further from the edge. Some edges appear to be more resistant to tree establishment if there are physical barriers such as a creek or ridge top that slow expansion of forest into grass or shrub-dominated openings. In areas where former openings were currently occupied by forest, there was little difference in terms of species and structure between the forest occupying the former openings and the surrounding forest. The results of all of these studies have implications for conservation of forest openings. In times of limited resources, conservation efforts should be made along the edges that lack physical boundaries instead of blanketing the entire opening with a given treatment.