Leaf Variability in Yellow Birch (Betulaalleghaniensis) in Relation to Environment

Four multivariate techniques were used to analyze 13 characteristics of standard leaves of 809 yellow birches in 112 populations on selected site types in the western upper Great Lakes region to determine the variability in leaf morphology of yellow birch and to elucidate patterns of leaf variation related to differences in the sites on which the birches grew. There were significant among-population differences for each of the leaf characters, but there were no consistent groupings of the populations based on several single-character analyses. There was a significant canonical correlation between leaf morphology and the site conditions of the populations. Principal components and Prim network analysis indicated groupings of the populations that were related to ecological conditions of the sites. Of all methods used, canonical variates were the most biologically meaningful and revealed the strongest relationship between morphology and environment. The populations were arranged on canonical variate axes along natural gradients of soil pH, relative drainage, or climatic conditions of the site. The phenotypic characters may be under genetic control and probably have evolved in response to complex environmental factors. Mass collections of standard leaves of yellow birch growing over a wide range of sites appear to be useful in determining patterns of genetic differentiation in the species.