Deicing Salt (Sodium Chloride) Damage to Pinusresinosa Ait.

Abstract

Four studies demonstrated that NaCl spray was the primary cause of browning of Pinusresinosa Ait. along salted roads. All damaged needles had high Cl and when analyzed, high Na; the symptoms produced by spraying NaCl on forest trees appeared identical with highway symptoms; damage occurred in the spring warm-up after a winter buildup of Na and Cl; damage was greatest where use of deicing salts was greatest. Coincidence between Cl in needles and on needles indicated spray was the source of the salt. Brown needles had higher osmotic potentials (Ps) in proportion to NaCl content, but high Ps was probably incidental to damage. Still unexplained are the occasional green highway pines with high Na and Cl.