It has been hypothesized that Juniperus virginiana facilitates tree seedling establishment in secondary succession. To test this hypothesis, we sampled four old fields in southwestern Ohio and monitored experimentally planted seeds and seedlings of Acer saccharum and Fraxinus americana for two years. Seeds and seedlings were placed into herbivore exclosures placed 0.3 and 3.0 m from J virginiana trees in an old field in Ohio. We found a significant positive spatial association between juniperus virginiana and tree seedling densities in all four old fields. Soil temperature, soil moisture, evaporative demand and light level in the 0.3 m treatment were significantly reduced, whereas litter depth was increased. Germination of A. saccharum, but not F americana, was reduced in the 0.3 m treatment, whereas seedling survival was unaffected in either species. Growth ofF americana seedlings was reduced by proximity to J virginiana but A. saccharum growth was not affected. Stomatal conductance was reduced in the 0.3 m treatment for F americana but unaffected in A. saccharum. Although there was a positive spatial association between J virginiana and tree seedlings in the old fields sampled, experimental seedlings did not exhibit an early demographic response that indicated facilitation.
Meiners, Scott J. and Gorchov, David L., "Effects of Distance to Juniperus virginiana on the Establishment of Fraxinus and Acer Seedlings in Old Fields" (1998). Faculty Research & Creative Activity. Paper 90.