Seed bank densities across an environmental gradient.

We determined the distribution of seed bank densities of woody perennial species across 5 permanent vegetation plots. We found that the distribution of seeds in the soil was determined by the spatial location of parent trees at all sites, but that absolute densities varied significantly between plots.Densities of viable seeds in soil was determined across five permanent vegetation plots, in 4 years. Soil cores were taken to 2 inches deep (including litter), soil was stratified at 4 degrees C for 6 weeks, spread out over sterile potting soil, and left in the greenhouse with plenty of light and water. Seedlings were censused as they emerged, censuses continued for 8 mo. Each soil core is 3.5 inches in diameter