| Significant species differences in foliar litter quality have been well-documented but differences within species, as a function of variation in genotype or environment, have not been directly addressed and, thus, remain poorly understood. We studied the significance of genetics, the environment, and their interaction in regulating forest nutrient dynamics and productivity using trees from four full-sib black spruce (Picea mariana (Mill.) B.S.P.) families of a complete 7 x 7 diallel cross experiment at the Petawawa National Forestry Institute (Chalk River, Ontario). Foliar litter composites from each family-plot on two sites of contrasting water availability were collected in October, 1993, and sub-samples were analyzed for initial N, P, K, Ca, Mg, cellulose and lignin concentrations. Inherent decomposition rates and nutrient dynamics of the litter composites were followed for one year. Samples of forest floor and mineral soil collected from within each plot were used to determine organic matter accumulation, pH, total nutrient contents in the forest floor and extractable nutrient concentrations in the mineral soil. Height, dbh, and total tree cubic volume, were used to characterize tree productivity. (Abstract shortened by UMI.)... |
