Vegetation response to sewage effluent disposal on a hardwood forest.

Foliage from treated-area sugar maple Acer saccharum showed significantly greater uptake of N, Ca, Mg, and P and a decrease in Mn than control-area trees. Radial growth increased significantly from 4.9 mm for the 5 yr prior to treatment to 6.5 mm in the 5-yr treatment period. Tree seedlings in treatment areas had significantly lower densities and species richness compared with controls; there were 102 410, and 27 080 seedlings/ha in controls and treatments at the end of the 5-yr irrigation period, respectively. The herbs Trientalis borealis, Trillium erectum and Aralia sp. had significantly lower frequencies in treatments.-from Authors