The effect of salinity on boreal forest plants is of growing concern today because oilsands mining in northern Alberta produces large areas of salt-affected soils that need to be reclaimed. We examined the soil and vegetation characteristics of seven naturally saline forested sites in northern Alberta to better understand the effect of soil salinity on mature boreal forest plants. Soil salinity, sodicity, pH, nutrients, moisture content, and temperature were measured in high, medium, and low salinity soils; salt ions, nutrients, and carbon and nitrogen stable isotope ratios were measured in aspen and white spruce foliage. Both tree height growth and basal area growth were determined. Aspen growth decreased with increasing salinity, but white spruce growth seemed to be more strongly affected by environmental factors other than salinity. Both species appeared to be robust against nutritional toxicities and deficiencies commonly encountered in saline soils, indicating a tolerance for some saline conditions.