Chlorosis of planted Engelmann spruce seedlings unrelated to nitrogen content

Shade-tolerant Engelmann spruce (Picea engelmannii Parry) seedlings generally became chlorotic when exposed to direct sunlight under several different growing conditions, whether grown in pots, in plantations, or in transplant beds at high or low elevations. Shaded seedlings under the same growing conditions remained a normal green color. Chlorosis was attributed to solarization, not to nitrogen deficiency. That conclusion was supported by the fact that the nitrogen content of shaded and unshaded seedlings was similar regardless of the growing conditions.