PARENT SESSION
Poster Session # 14: Forest Ecology.
Wednesday, August 6 Presentation from 5:00 PM to 6:30 PM. SITCC Exhibit Hall B.
Tree-soil relationships in a northern hardwood forest are reinforced by seedling survival patterns.
Bigelow, Seth*,1, 2, Canham, Charles1, 1 Institute of Ecosystem Studies, Millbrook, NY2 USDA-FS Sierra Nevada Research Center, Davis, CA
ABSTRACT- Tree communities in northern hardwood forests are organized along gradients of calcium and co-varying soil factors. Because clear relationships already exist at the sapling stage, we tested how survival at the seedling stage is affected by base cation availability. Seedlings of six species were transplanted into plots in a southern New England forest that had either been fertilized with calcium sulfate or magnesium sulfate or left as unfertilized controls. After two years there were no effects of fertilization on survival. In a companion experiment soil chemistry was measured in randomly located plots of naturally established seedlings, and maximum likelihood estimation was used to model two-year survival as a function of soil chemistry. Significant increases in predictive ability were gained by inclusion of soil chemistry. At higher levels of soluble aluminum, sugar maple survival declined and beech survival improved, which is consistent with the positions of these species along the soil gradient. Eastern hemlock had increased survival at higher soil pH, which is not consistent with its position on the soil gradient. We conclude that survival of sugar maple and beech seedlings in response to soil chemistry plays a key role in establishing the soil relationships characteristic of these species as adults; nevertheless aluminum, rather than calcium, is the factor that the species respond to most strongly.
Key words: plant-soil, calcium, northern hardwood, seedling survival