Restoration of stands invaded by black locust will proceed in at least two stages: 1) removal of black locust, and 2) reduction of N loads to within range of target communities. First, beginning in fall 2000, all black locust within three of the six black locust stands described above will be removed and roots killed using a cambial herbicide treatment. Sites designated for removal are spatially dispersed throughout the study region. However, they have not been randomly chosen, but represent the more contained black locust stands which are expected to respond most favorably to treatment.
Second, a preliminary study of N reduction using cover crop harvesting will be undertaken in the summer 2000. An abandoned agricultural site within the Preserve will be planted with at three densities of native plants. Treatments will be planted in 2 x 2 m plots with four replicates of each in a nested design (four areas identified, each with one of each density treatment). Within each plot, composited soils (composite of four subsamples) will be sampled at three depths (0-10, 10-20, 20-30 cm) prior to planting. In the fall, above ground biomass will be harvested, dried and weighed to estimate primary production. Plant parts will be separated into leaves, stems and fruit and N concentrations will be measured for each. In addition after harvesting, soils will be sampled as above. Standard soils analyses will be run on the samples (see description above). These data will yield an estimate of N loss on an area basis for three different planting regimes and provide a basis for evaluating cover crop planting as a management strategy for restoring suitable N levels to soils derived from sites invaded by black locust. Depending on the outcome of this experiment, cover crop planting and harvesting may be considered for sites subject to black locust removal.