Effects of highway deicing agents on Thuja occidentalis in a greenhouse

Abstract

Greenhouse studies showed that eastern white cedar (Thuja occidentalis L.) exhibited yellowing and necrosis of foliage and browning of roots in response to high salt concentrations in soil and nutrient solution. Foliar spray showed injury symptoms to the foliage but the root system was not affected. Water stress as measured by water saturation deficit of the leaves also increased with increased concentration of salt in the soil. The damage to white cedar foliage occurred when the concentration of Na was 3 mg/g (0.3%) of dry matter. The toxic concentration of Cl was 8 mg/g (0.8%) of dry foliage. White cedar trees grown in muck soil treated with salt exhibited less injury than those grown in loam, sandy, or greenhouse soils receiving the same treatment.