The vast majority of damage we see on spruce trees in Montana is not caused by diseases, but rather by environmental causes such as drought and freeze damage. The damage may not become apparent for many months, which often results in misdiagnosis. Symptoms are usually dieback that begins from the needle tips and moves back toward the branch, in a rather uniform pattern. Sometime whole branches or portions of the tree may be killed.
Color varies from brown to yellow to reddish-brown.
Heavy fall moisture can result in flushes of growth susceptible to winter damage. In addition, warm periods during winter, including chinooks, can cause spruce needles to loose moisture through transpiration and because the ground is frozen, roots can not absorb more moisture from the soil. Trees that go into winter under dry conditions also account for much of the damage we see every year. Most tree roots, of even the tallest trees, are in the upper 18 inches of soil , meaning that trees can become drought-stressed much more quickly in both winter and summer than we would suppose. Without a deep watering that soaks into the ground at least two feet in late fall, just before the ground freezes, the tree is very susceptible to drying out, resulting in dead needles and branches the following spring or summer.