Manipulations of over-story regulators on a Black Oak (Quercus velutina) Sand Barren community

In the absence of a disturbance regime, flora at historical oak sand barrens are changing predominantly due to a buildup of leaf litter and shading of the raw soils. The long-term absence of a disturbance regime will continue to push oak sand barrens toward a more mesic "Dry Southern Forest Group Terrestrial Class” alternative stable state (Beisner et al., 2003). Three different restoration techniques were applied to re-create disturbance at ten glacial kame sites within a degraded Black Oak (Quercus velutina) Sand Barren system in northeast Ohio: prescribed fire, select canopy tree removal favoring 5% to 30% tree canopy cover, and forest floor leaf litter removal. Vegetation was monitored in modified North Carolina Vegetation Survey plots prior to and following treatment applications and were compared against both temporally and spatially equivalent control sites. Vegetation responses in terms of ground layer richness, abundance, and cover estimates were measured. Treatments varied in success as canopy tree removal induced the greatest vegetation response towards a return to the historical flora; leaf litter removal produced a modest pulse response from a few select species released from the shade-creating effects of accumulating leaf litter; prescribed burns did not create a disturbance that resulted in any significant plant response, presumably because low-intensity burning minimally reduced leaf litter cover. Manipulations that more directly replicated historical conditions rather than efforts to recreate historical disturbance processes performed better to set back the historical state, and the predominant barren species to recover post-treatment included xeric-condition-tolerant graminoids.