This study was conducted to investigate the negative physiological impact of saline to roadside trees and to assess the physio-biochemical tolerant characters of woody plants against salinity. Two-year-old Zelkova serrata seedlings treated with 0, 3, 14, 56, and 112 mM NaCl were measured for root collar diameter and cambial electric resistance (as an indication of vitality) and analyzed for carbohydrate and mineral content in the leaves. Z. serrata was affected by NaCl treatments. The vitality of Z. serrata decreased with an increase in NaCl concentration, and the NaCl treatment resulted in nutrient imbalance shown by changes of ion concentration in the tissues. However, relative growth rate for diameter and carbohydrate metabolism in the leaves were not greatly influenced by NaCl treatment. Short-term treatment or low NaCl concentration may not have an observed impact on growth. Nevertheless, roadside trees exposed to saline during the long term would likely show negative effects for growth performance from altered ion concentrations.